I have heard it said many times on this forum that aeration should turn the pond over at least once every 24 hours. What is the science behind that statement?

Have also heard that anything less than a 24 hour turnover rate can actually do more harm than good. Is that true? If so, how is this so? What negative effects are realized?

For instance what if it only turns over every 25 hours? Or 48 hours? Or 96 hours? It seems to me the slower turnover would only provide proportional less benefit in relation to the amount of anoxic water aereated, but I have gathered from previous comments that not only would anything less than 24 hours not be helpful, it would actually be harmful. I am missing the logic. What harm is done by partial aeration?

What happens under natural aeration via wind and wave action? Can there be times of partial aeration turnover that can be damaging? A too fast turnover caused by a cold rain in the summer causing turnover we know can cause fish kills. Can wind action after a prolonged still spell do the same?

How does wind action come into play when sizing aeration systems? Not at all? A wide open pond in windy areas gets same system requirements as pond in valley surrounded by trees with little to no wind action?

Maybe too many questions for one post?

""I have heard it said many times on this forum that aeration should turn the pond over at least once every 24 hours. What is the science behind that statement?""
That statement is a big generalization for average pond conditions and a conservative BIG 'estimate'. Many exceptions occur. The above generalization assumes all pond water is the same which is definitely not true. A few ponds with unique conditions do not need to be aerated compared to some hypereutrophic ponds that need three, four, or more turnovers per day. Extreme example: sewage treatment ponds.

The above is a big reason why information is needed on goals, species, feeding, and more to have a "properly" sized and installed aeration system done by an experienced professional instead of the average DIY or home built system for a better bang for the buck.

IMO some or many "experienced" professionals (aerator sellers) do not fully understand the topics snrub described. Truth be known, many of his questions do not have definite answers. Pond conditions are highly variable and conditions constantly change. There are pretty good generalizations; thus "one turnover per day".

I wonder if the 24 hour might have more to do with the "ramp up" time. Instead of doubling the time each till full turnover is achieved, preventing large swings in DO????

I figured there were lots of "it depends" involved.

I guess my main question would be, what if a person was only turning the water half as much as needed? That could be a pond that needed turned over twice a day getting only one turnover or a pond that needed one turnover every 24 hours taking 48.

Would the results be only partial benefits of aeration or would there be actual negative reactions making it such that it would be better to just turn the system off?

That is my main thrust of this discusion. Can a person actually do harm to the BOW, or is it just a matter of wasted money if a system is undersized?

I am very interested in this. I KNOW in my scenario two windmills is under sized.

I would like someone that is an aeration specialist to 'step up' and more fully explain how too little aeration would do more harm than good. Sue Crux would be a good candidate to start this discussion since Vertex is the company aeration "standard". Where are the Aeration Professionals when you need some specific information? Then a discussion could occur.

Too little turnover usually will resort in deep areas or percentages of the pond that are anoxic - devoid of oxygen while the area that is mixed will have a more oxygenated 'zone'. For example the deep area near the dam would be the only area mixed thus having a general higher DO near the bottom compared to areas unmixed further away from the dam. IMO this aerated zone could at times serve as an oxygenated refuge so whoever is in it has a better long term chance to survive. IMO As long as there is some top to bottom aeration the extent of the fish kill will be less whenever a fish kill occurs.

That makes sense to me.

It would seem to me an undersized system should still be of some benefit, just not full benefit.

Just like wind can aereate a pond, if it takes a sustained 10 mph wind to do so fully, it seems a 5 mph wind is better than no wind at all.

Thus logic would imply an undersized system would still be better than no aeration at all.

But I thought I might be missing something. Like maybe partial turnover might encourage unwanted algae growth or something other weird going on.

I am getting ready to put in aeration system as soon as electricity is available, so am no expert.

However, I do remember Bob Lusk looking at the long, narrow island in my pond and asking, "Do you plan on aerating?" Anything that cuts down on the interaction between wind and water increases the need for aeration.

Please excuse my DA, but I thought the purpose of the windmill was to keep a hole open in the ice and not so much for aeration. Would aeration in the winter cause over cooling the water in that nice mountain pond? Just curious here when it comes to aeration, its new at my place.

Tracy

Well, I am in the DA club as well!! My DO is very low and my lake needs aeration badly. It is basically just a leech farm right now.

Last winter one windmill was not able to keep a hole open in the ice for me. So this summer I have the diffusers set in the deepest water and this winter I am going to put the diffusers some what close together in shallow water and pray for a hole or two! I don't THINK I could super chill the lake, but I'm no expert.

I wonder if the fish would rather freeze to death or suffocate? lol

The fish will tolerate colder water better than compared to lower oxygen.

Bill, Ha, can't live with out O2. Good point! lol See WBJ I said I was in the DA group Nice place you have there in the Mts

Tracy

No expert here either, but have a theory to ponder. If you aren't keeping up with or exceeding the O2 consumption rate on the bottom, then the water you are bringing up is "bad water" as in low O2 and hydrogen sulfide laden. If you are constantly compromising the top water where the fish want to be, that could be badness. In that case, a significantly undersized aeration system might not break up the thermocline, and not push through to a full circulation where water coming up is decent. The little O2 going down is consumed and levels are still not enough to support aerobic bacteria or fish. Then aeration may just continually bring up more bad water and fish are worse off.

Lets see a show of hands of people that assume that the majority of O2 that enters a pond from aeration comes from the bubbles that the aeration system brings to the pond.



Winter aeration is different than summer aeration. Different goals and different methods to achieve those goals.

Winter aeration for ponds that have a heavy snow/ice cover is different than winter aeration for ponds that get 1" of ice on it for 3-4 weeks of the winter.

During winter in cold climates where ponds freeze over, you do not want to aerate the lowest region of the pond anyway. Water is densest at 39°F, and aerating the upper 1/3 of the water column allows the bottom of the pond to stay as a warm water refuge for the fish. Trout can survive in much colder water than RES can.

This is where the different geographical areas of the country really point out the differences in pond management strategy.

I agree with DNickolaus, that under aerating could create a lower water quality in the whole pond than if the pond was not aerated at all.

Do you think I could be doing this Esshup?

I would like to have more aeration pros weigh in on this topic. Where are they when you need them? I present an alternative opinion.

Too little aeration does reduce the amount of anoxia in the pond; be it a very small amount and results in some stressors. Fish do get some water quality stress (the 'badness') from the poor quality of upwelling water, depending on the volume of upwelling and degree or concentration of "bad" water. A low degree or volume of upwelling stress is in most cases easily tolerated by the fish which would be similar to being in "stuffy" air. You tend to move or search toward fresher air/water which is not far away when minimal aeration is occurring. Again it depends on degree or severity.

However if the 'top' water is also 'bad' for what ever reason then fish have nowhere to find acceptable water. Adding 'bad' water constantly to good surface water by under aerating increases the chances of fish kills, but too little aeration reduces the impact of a summer or the fall turnover whenever that occurs. The amount of anoxic reduction depends of strength of aeration and amount or volume of anoxia in the deep unmixed zone/depth.

Turnovers of various forms can be 'strong' or extensive enough to kill a few fish or all the fish. Thus under-aerating IMO will in the long term life of the pond result in fewer dead fish than no aeration at all. Fewest dead fish long term, due to poor water quality, occurs in ponds with the most top to bottom circulation. The less the pond is turned over, I think the more dead fish that will occur over the life time of the pond. It is a form of degree from none to "over aerating" with some aeration IMO being better than none even if some or minimal air does cause some periodic stress. However that stress will overall in the end be less than that of no aeration.

Possibly. Read what Bill Cody posted above. Since the single aeration windmill last year was not enough to open a hole in the ice and keep it open, this year I would try to get a hole open and keep it open. I think by having a hole open it will greatly help in your situation.

With not having anyone on-site during the winter, and the altitude that the pond is at, you have a uniquely difficult situation.

Without on-site monitoring, you don't know if it is a problem of the line freezing up and not getting air to the diffusers, air getting to the diffusers and just not being able to open the ice in a large enough area that it also melts the snow which stays bridged over across the hole, or not enough air getting to the diffusers to have them move enough water to punch through the ice.

I know your airline isn't this size, but I have seen grid based compressors have a 3/8" like freeze up, even when operated 24/7. With alcohol injected into the line, the plug thawed and air to the pond was restored. An automatic system like that would help if that was the problem.

Thank you so much Bill and Scott! You guys are always helping. Sorry to hijack this post Snrub!

EDIT: That's why Scott gets my business!!

No hijack at all. It is all part of the water quality discussion.

I had not thought about "bad water" being brought up and being a problem. That makes sense.

On the other hand, it would seem to me that would be a case of extremely undersized aeration. If say it was only turning the pond over in 48 hours instead of 24, would the water really get all that bad in a relativel short time frame? If it were turning over the air on the order of something like once every 5 days I could see where the lower water might be bad. At that rate though, the amount of "bad" water upwelling would be relatively low in volume also so its effects might be relatively modest.

Maybe a windmill system starting up after a week of no wind could be a problem.

Interesting subject.

Me thinks "it depends".

Anyone claiming to be an aeration expert out there?

You get my vote. Unfortunately we lost our other Ohio aeration guru a few years ago.

Crickets......

Bump..........

Bringing this thread back up because I have a specific question. I'm planning on upgrading my pump system to a single pump of the vane type. It seems that will be the best bang for my buck in a 10' deep maximum pond concerning cfm developed vs electric cost to operate.

Based on the three 9" double Matala diffusers in my main pond with a single in my sediment pond and a single in my forage pond, it brings the total number of diffusers to 8. Based on the air I need to adequately inflate them it appears I could go to either a half horsepower pump or a 3/4 hp pump. The half hp should be adequate for my cfm needs I believe and I do not want to break the bank in electricity costs.

There is a question.......I'm coming to it.

So if either compressor would be within the CFM capability of the diffusers, would I be better off buying the 1/2 hp and run it 24/7 or buy the 3/4 hp and put it on a timer? In other words a continuous pond turnover, or a higher rate of turnover (and water flow) run intermittently?

The 3/4 hp pump is not that terribly much more expensive than the 1/2 and I am leaning towards it. I figure running fewer hours it should have longer service life between rebuilds. And I can keep about the same electric costs by an appropriate cycle duration.

If I go the 3/4 I will have another question, but lets discuss this element first.

Edit Correction. It appears there is no difference between the 1/2 and 3/4 units as far as air flow. What I should have said ask is if I should go the 3/4hp continuous or the 1 hp and run it intermittent.

The 3/4hp pump will easily operate all 8 diffusers. Daily run time is actually based on the amount of biochemical oxygen demand of each pond. Pond BOD is fairly closely related to water clarity (visibility-transparency) and amount of bacteria-phytoplankton-detritus present in the water which consume DO esp at night. Pond age also has an influence on BOD; older usually requiring more daily BOD. The only way to really know this is my measuring the DO in the deepest water several times throughout the 24 hr after aeration stops.

For what I know about our ponds, your location / climate, and pond age, IMO good aeration for 4-8 hrs per day should be very adequate when using the 3/4hp compressor if you do not have dense algae blooms.

Many thanks for that info Bill. That gives me a starting point and some direction. You are such a great resource for this forum!

Your reply and the great explanation about the oxygen demand leads me into my second question.

I have heard it stated numerous times on this forum if running the aeration system less than 24/7, run it at night time rather than day. I have heard it stated, turn on the aeration from midnight to sun up or something similar. Dependent on the capacity to turn the water the duration of the "on" time.

This seems backward and counter-intuitive to me.

Let me state what I "think" I know and how it would seem to me would be a better way to operate, then you (or anyone else) can tell me where my thinking is wrong (which is a high probability).

During daylight the upper layer of water gets super saturated (on a sunny day) with O2 by algae production. At night the opposite happens. So why would a person want to bring up lower level water (lower in O2 to begin with) to the upper level where O2 is also dropping? I understand the water/air interface is adding O2 to low DO water. But would you not want to bring low O2 water up during a period of maximum O2 production rather than at night when only the air/water interface can add O2?

It seems to me it would be better (from strictly an O2 standpoint - lets leave summer water warming out of this for the time being) to circulate super O2 saturated water from mid afternoon to the lower level thereby creating an "O2 sink" of good deep water to hold the levels over night till morning. It seems to me a person would be wanting to move water to different levels during the day where algae has the chance to produce the most O2 over the maximum number of hours.

I hope I explained that well enough for what I am saying to be understood. It looks like to me a person, to maximize O2 production and retention, would want to run the aeration during the day rather than during the night. Why not run the air from say 8am to 2pm or from 10am to 5pm rather than at night?

If someone wants to bring up BOW heating during summer (I know Texas guys are concerned with this) lets discuss that as a third separate from DO question.

snrub, I am one of those Texas guys you mentioned. So, like you, I am trying to figure out when is the best times for me to run the diffusers. When I added the diffusers (6 of them), I was told to run them 24/7 (by two different companies) and that is what I did for the past two years. But now, after watching Bob's Facebook program, I have agree with a pond needing a some cooler water during the hot summer months. Last year I monitored the DO and water temps from top to bottom. The water did have a cool spot but only the bottom foot of water where the DO was low. So now I am thinking of running them from 7 or 8pm to 8 am. Hoping to keep the DO up and the water a little cooler in the hot summer months here. Due to different pond bottom depths at different places turn over rates have to be different at different locations in the pond. I also see snrubs thinking or thoughts on running the diffusers at different times of the day to provide more O2 throughout the depths of the pond. How long would you run the system to move a little water around during the day, but maintain some cooler spots?

IMO, knowledge, & experience aeration is a complex topic due to numerous variables such as size & depth of pond, pond configuration and bathymetry of the basin, trophic (nutrient-BOD) state of the pond which changes, size of the aeration system and how quickly it can turn the water column, regional (climate) location, water temperature, type and efficiency of the diffusers, water quality, fishery type, and goals for the pond, etc. Aeration generally reduces chances of DO problems which is why it has proven popular for benefiting ponds. With all these variables occurring,,,, each pond is truly unique, thus the default aeration method is to aerate 24/7 to compensate for all the variables since very few pond owners and sellers have the ability to test DO, evaluate BOD, and determine needed operation time for each pond. Simple is often easiest. Under sized or minimally sized aerators need to be run 24/7 to get the pond turned over adequately.

IMO Snrub's rational is sound -""During daylight the upper layer of water gets super saturated (on a sunny day) with O2 by algae production. At night the opposite happens. So why would a person want to bring up lower level water (lower in O2 to begin with) to the upper level where O2 is also dropping? I understand the water/air interface is adding O2 to low DO water. But would you not want to bring low O2 water up during a period of maximum O2 production rather than at night when only the air/water interface can add O2?""

Short answer is yes, ideally you want to force the best quality water to the bottom and the best quality water is usually at the surface. However in most cases anytime you can dilute the worst water quality with better quality water, this is good. In most, not all situations as long as you are mixing daily, the differences between the two techniques is not significant enough to cause DO problems. The discussion is often or becomes academic - a mater of degree.

There are two main goals involved in this discussion: A. most efficient DO adding aeration method, and B. provide cooler water for the fishery. Each requires different aeration periods.

We also have to account that the bubbling action of the diffusers will add as much or more DO to the rising water column as simple atmospheric diffusion which according to text books is stated as very inefficient for adding DO to the water. Wave action improves atmospheric O2 diffusion. Note: bubbling from aeration adds a lot less DO to the water compared the the millions of algae cells per ounce of water during daylight.

Normally DO is consumed most rapidly at the mud water interface and at depths where light does not penetrate. This DO loss is primarily by bacterial respiration during decompostion. Normally there are lots of bacterial in the water column, but many more at the mud water interface where decomposition is most abundant. A good example of this IMO is in winter during ice cover when DO is lost first in the surface mud and then progresses upward as winter progresses. Final DO loss is then at the near surface under the ice/snow cover. Fish will move upward in the water column as this process progresses.

During summer and warm temperatures water is only able to hold about 1/2 as much DO as during 39F water. Plus all biological & chemical DO absorbing activities occur faster in warmer water. So DO can be consumed quicker in summer compared to winter, thus the greater need for aeration in summer.

In most ponds whenever low DO water is brought to the surface it gets infused with higher DO water, degassed, and pushes, pulls, or moves better water to the depths. In most cases there is not enough DO degradation to cause problems because of the high amount of DO in the surface layer and generally there is enough DO to satisfy the needs of the entire pond. Exceptions occur after several cloudy rainy days when algae production is reduced, turbid or low water clarity occurs, and when low algae production is present for various reasons.

Thanks so far Bill. Great comments.

I get a lot of wind mixing here too but likely not when I need it most in dead of summer.

Few trees to block wind and Kansas is known for wind.

Ripples and small waves due to wind do not oxygenate anywhere near the amount of white cap waves.

I was thinking more about the water mixing capability of the wind. I have watched plumes of muddy water caused by a small spot of bank erosion move out to the center of the pond. I know from diving that surface current produced by waves can produce long shore currents and undertows.

What I don't know is if these currents would help the deep colder water below the thermocline.

Here is a link to the observation of wind created current.

thread showing current flowing out to the middle of pond created by wind

This is a quote from that post:
Happened to be out yesterday and noticed a muddy streak of water heading off across the pond. It was a very windy day. It looked like the muddy streak was coming from somewhere out in the pond toward the bank.

Upon further examination the muddy water was in fact coming from a small portion of the bank which had exposed clay. The waves were washing the clay into suspension then the undertow current was taking the muddy water out in the opposite direction of the wind and waves. So what looked like muddy water coming in from the center of the pond was actually muddy water moving out.

Aeration through diffusers is good from all I have personally experienced and read. In my pond after the diffusers have been run 24/7 it seems that the pond has a decent DO reading throughout the pond during the most difficult times during the hot summer months. But I ran across a different problem that I believe the diffusers are instrumental in and that is disturbing detritus from the pond bottom and causing the water to become cloudy with lower visibility. And it may cause my fish to grow slower and harder to catch also. In a catch 22 during the summer, is as the water in the pond drops there is more and more detritus spread around in shallower water and as the pond drops the diffusers which were once in 10'of water is now in 7' and the diffusers are less beneficial at that depth. I am trying to find a way that the diffusers will kick up less material. If I raise them up from the bottom then when the pond drops the diffusers become less beneficial. I am working on a solution, I hope!

Bob Lusk addressed part of this discussion in one of his Facebook live presentations. Pond spring check list - listen starting at 12:40 for info on this question

I don't do Facebook so I listen to the presentations after the fact.

snrub, I like the way you approached the aeration times and would have to agree with what you said for the most part when speaking of DO during the time plankton produces it's highest output of oxygen and how one might use the diffusers in the pond for better oxygen distribution. I bought a DO meter( recommended by Todd Overton) last year and ran samples during the day and even a couple of nights. It was worth all the money, time and effort I spent to see and understand my pond and the fish and diffusers. I never expected to see low DO numbers at the bubbles but understood it all after testing. Hay, I am not the sharpest pencil in the box Had to see it all I guess to understand it. As said earlier here, I have a problem with the diffusers kicking up dirt, detritus etc off the bottom, contributing to the cloudy water I have sometimes. I have tried different things like cinder blocks, baby swimming pools in different configurations an nothing seemed to reduce the plum of cloudy water. So, right now I am building platforms to set the diffusers off the bottom some 18" on the first run and will adjust the height of the platforms as needed. Platforms are made of expanded metal and angle iron, where my Kasco diffusers will set. After I get them running I plan to look at your discussion, thoughts, here a little closer and maybe see where the DO might lead me. I have to give Bob Lusk some credit here, where he said GOD designed a thermal cline for good reason. I need to keep that in mind also when using the diffusers.

From my lake diving days many years ago, I remember during the dog days of summer we would find the fish right around or in the thermocline.

I wonder if they dip in and out of the cooler water as needed to maintain their preferred temperature? Might be something to leaving at least one deep hole not circulated for that reason. A cool water refuge.

You will have some fun with the DO meter. I hope you learn lots and share what you learn here.

As far as low DO in the water/bubble plume that makes sense. I have noticed swimming when I approach the diffuser plume the water is significantly colder (summer time). So it makes sense that it is pulling up low DO water from depth. I suppose if there were enough or maybe excess circulation then there would be no temperature difference as the water would already be thoroughly mixed.

What is puzzling is why the small fish like the bubble plume so well. In the summer we would approach the diffuser bubbles on the boat and see small BG riding the bubble plume up from depth then disperse outward. It appeared they were riding the plume over and over, like making a game of it. Maybe they liked the cool water? Or the bubbles? Don't know. Just know it is a common sight during summer around the diffusers.

My first diving experience was in mined pits in E. central Okla back in the late 60's. If we dove below 10' or so it was freezing Same thing diving Toledo Bend lake here in E Texas and the lakes in Ark. just too darn cold for me. I like the warmer Caribbean waters I am going to give your thinking some serious thought this summer using the diffusers. I need to keep the waters a little cooler but maintain the DO as best I can. I keep thinking what DD1 says, your not a pond myster till you kill some fish, Trying to avoid all that!

The only reason to lake dive below the thermocline is to look at rock features or retrieve boat anchors. You are right, it is cold. In the summer if we wanted to do a deep dive we would don a relatively thick wet suit, sweat like a pig and almost overheat before we got in the water, then finally get cooled off at depth.

Normally everything worth seeing (the fish and dropped fishing rods) were above the thermocline. Mid summer it might get as deep as 25 or 30 feet in a more clear lake like Beaver in Arkansas.

When swimming in farm ponds as a kid sometimes there would actually be two thermoclines in a really super muddy pond. The top inch would be so hot it felt like it was scalding you, then to three feet down it was warm/hot, then below it freezing cold (or at least it felt like it). The modus operandi was to quickly get in and become a human diffuser and quickly move about to stir it all up to a more comfortable average. The cold water mostly stayed on the bottom but the the scalding hot stuff right on the top got stirred up where it was comfortable.

This is in a pond that looked like chocolate milk. My what we would swim in back then. Us and the cows.

snrub, your description of dropped fishing rods being above the thermocline reminded me of a dive I made in Jackson Lake, in Grand Teton National Park, to attempt the retrieval of a friend's rod. He had marked the spot with GPS. I double suited up, guessing the water would be cold. The lake may reach 68 or 70 degrees at the surface in mid-summer.
Overboard I went. My friend had the bottom depth measured at 34 feet. At 22 feet I hit the thermocline. The cold intensified. Darkness set in. When I touched the bottom, I could not see my hand in front of my face. I could not see my bubbles. I didn't have any way of knowing which way was up! Needless to say, I wasn't seeing anyone's fishing rod.
I added air to my BC and rose up through the water column that way. Just below the thermocline, my sight returned.
That was really spooky down there in the cold and pitch blackness!

Bill Cody do you or anyone else know the difference between the Gast model 0823 and 1023 other than the cfm difference? For some reason I can buy the 1023 (10 cfm) for less money than the 0823 (8 cfm). If they are the same build quality with the same expected life it is a no brainer for me to go to the 1023. But I have found several places where the 1023 is either no more expensive or actually cheaper than the 0823. This makes me wonder if the 0823 doesn't have some special feature (I have heard reference to nickel lining in some vane pumps for example) that makes it a longer life pump.

I can not tell from the Gast site where they list specifications.

I'm pretty sure I want the 1023 but do not want to order it and later find out the 0823 is a much better/longer life pump. I have ask the question via email to one of the potential purchase sources and if I find out anything from them I will add it here.

Update on the pump differences between 0823 and 1023. Supplier got back to me and said only difference in pumps is air volume output. He said the 1023 was such a popular pump they bought them in larger volumes and got better pricing. They passed the better discounts on to the customer and that is why they could sell a 1023 cheaper than an 0823.

So for my purpose, the 1023 is a no brainer.

Snrub - your source is correct about the difference of the 0823 and 1023. The rest of the numbers in the model number do have significance in the configuration of the pump such as presence and type of quiet running head and type of motor. To my knowledge there is no nickel lining in either of those models of pump.

Here is an update on the pump upgrade for my aeration system. I did end up with a Gast 1023 pump.

I was running 4 AP100 Pondmaster linear diaphragm pumps, three each on a dual Matala diffuser for my 3 acre main pond and one that split air for two single diffesers in my 1/10th acre sediment pond and 1/20th acre forage pond.

I left one of the AP100's running the small ponds and put the 1023 on the three double diffusers in the main pond. It puts out considerably more air than the three AP100's at the 8-10' depth they were operating at.

The manifold is just a four outlet water hydrant valve. A manufactured manifold or just individual ball valves plumbed together would make for a little more professional setup but the water valve does have stainless balls on nylon seats so it works just fine. But by the time you buy the adapters to garden hose to pipe to hose barbs there is likely no cost savings. What I am trying to say is this is not particularly the best way to do a manifold but it does work and works well. I do close my south outlet to restrict flow to it because it is a couple feet shallower and was hogging more of the air than the center or north diffuser. By closing off that valve a strategic amount all three diffusers look to have about the same water boil.

Probably did overkill mounting the pump. It sits into holes (so I can easily lift the whole pump out without unbolting anything) isolated by some home made rubber isolators and sits on a rubber pad made from some scrap rubber bed liner for a pickup truck.

Pics with descriptions below.

There is still a little to do. I salvaged a timer out of our defunct turkey barns that used to run fogger pumps to use with this pump. Currently I am running the pump from about 7:30 am till 1 pm then again for another hour or so at about 6pm for something over 6 hours a day. I want to mount the manifold rather than just having it lay in there like it is.

My advice? If your time is worth anything buy a factory system. But I like to learn and tinker with the stuff. So the DIY is part of my enjoyment. I would not say it has been a cost savings, but what I have does work well.

Nice! I'm guessing that the 1023 will be generating more heat than the 3 replaced diaphragm pumps? What are you doing for ventilation?

Puzzle solved...FOOD! Lots of macrophytes and other foods in that plume being brought up.

It definitely heats the air more as it compresses. The vinyl hose coming out of the pump I am thinking about replacing with heater hose or at least EDPM because the hose gets so hot.

The small building has a 12" or so louvered vent on each end and I have insulation in the top lid to keep the sun from heating the metal shed up. But I have considered putting a 6" muffin fan attached to one of the vents to force air through the building. I'll monitor it as it gets hotter weather and see how hot the shed gets. The pump motor is thermal protected but it is not good to run them right at their heat limit.

It is noisier than the linear pumps but not horribly so. My daughter is building a small house about 50' away from the pump house. I'll try to time the pump usage so she is at work and when she is home sitting on her porch the pumps will be off.

That makes a lot of sense Rex. It also makes sense after seeing about three schools of what I think are YOY fingerling BG feeding around the dock yesterday. Schools of a couple hundred or so fish were feeding in a ball near the surface off something on the surface. At first I thought they were LMB fry but about the time I get close enough to tell for sure they go under. But I think I saw some vertical stripes on at least some of them so likely BG. Fish are an inch or two long. I suppose one of the schools could have also been LMB because it looked like dark over light bodies. Wish I could have gotten close enough to tell for sure.

But I digress. The reason I brought up these YOY balls of fish feeding on something concentrated on the surface of the water, it would also make sense if the water flow from the aeration was bringing up tiny food in the water boil there would be small fish to take advantage of the food source. Plus some cover from the bubble plume. I've seen what I assume is LMB cause schools of these fish just ripple around the water column and even strikes at the surface. So where the small fish are feeding, the big fish are too.

The food in the aeration boil is zooplankton brought to the surface from the deep zone.

I guess I am one of the pond ecological experts here since I've taken numerous college courses in biology and then achieved an advanced degree in aquatic biology. The impact of under aeration has a lot to do with biochemical oxygen demand of the pond water. The more enriched and eutrophic a pond is, the more under aeration becomes a problem. As mentioned it has to do with how fast the water on the bottom is loosing its oxygen. Numerous variables control this. About the only way to determine rate of DO loss is measure it which I have done a few times in local ponds.

What are the advantages and disadvantages of intermittent aeration. Right now I am only at the pond a few days a week. So I run the aeration several hours a day while I am there.

If you put the pump on a timer, you could be consistent with your run times and wouldn't have to rely on being there to turn it on...but as has been said in a couple of threads, a little is better than none at all.

Thanks for the answer. I am about 5 miles from the nearest power line and haven't set up the solar system to run it yet.

I'm new enough to aeration to be dangerous, but I would be concerned that periodic (or intermittent) aeration would lead to the accidental "turn-over" of the pond. e.g. If the lower water column loses it's O2, like lower water tends to do, and then you turn on a aerator and bring it up and mix it in, now you have a lowered O2 state which could lead to a fish kill.

Another newbie thought on the disadvantages would be...intermittent aeration would be like always starting the system up from near scratch. I would be afraid to show up on Saturday an just turn the system on for 4 hours which would lead me to 15-30 minutes on Saturday, 30-60 minutes on Sunday and then off for the week until my next visit. This would be less risky than several hours a day, but would it really be doing much? I would bet that 4-5 days without aeration would lead to a stale lower water column and followed by a couple days of aeration would lessen the quality of the upper water column. Seems to lack stability to me.

That is what I am concerned with when I get back and turn it on there is no odor from the bubble plume. Other than an O2 meter is there a way to check lower water. Does anyone know of a reasonable priced meter?

I have to agree with Quarter Acre.

I run my aerator 8hrs every night on a timer. This is my first summer and the improvement in pond health is already easy to see.

What a great discussion thread. Lots of good questions and ideas.

I think one thing to keep in mind is that when talking about aeration start up there are two specific topics of concern. One is the O2 levels but the other and more concerning aspect of diffuser start up, for the very first time (or after an extended period of inactivity), is bringing up toxic chemical saturated water too fast for it to off gas and get rid of its toxic properties so the toxic water does not kill fish. If we have stale, toxic water below the thermocline and bring it up so quickly it mixes and ruins our good top water we can kill fish because of the toxic water. It is in addition low in O2 but the reason we kill the fish may be because of the toxicity of the water rather than simply being low in oxygen content.

So that raises the question, how quickly does the water gain enough toxic gasses that it becomes a danger? For example, we might be able to assume that an old pond that has never had aeration would have toxic water below the thermocline and it would be dangerous to the fish to put in a diffuser and mix this lower water rapidly. But lets say a pond has regular aeration but the electricity goes off for 24 hours. Would it be dangerous to restart the aeration and run it continuously or would you need to do a slow start up again? My guess is it would not be a problem with only a 24 hour lapse (but of course it likely would depend on the pond). But what about 48 hours? Or a week? In other words what I am getting at, how long does it take for the detritus on the bottom of the pond to infuse toxicity into the low water resting below the thermocline to make it toxic enough for fish that when it is mixed with the upper good water it is still toxic enough to kill fish?

Of course that last questions answer is "it depends, depends, depends, depends". On a gazillion things. But it would still be nice to have some general rule of thumb. For example aeration pump quits and we get another within 24 hours = ok but if it goes a week need to do a slow startup. That is not a recommendation but just an example.

Wow that was a lot to type. Hope someone got something out of that ramble.

I'm following you John!



I would think that you could loosely correlate water temps to O2 content. What I mean is that without aeration my pond has held about a 10 degree F difference from 18 inches below the top surface to 7 feet down. I expect aeration to change that and narrow the gap. Let's say that I get my aeration system up and running 10 hours at night and find that the delta T between 18" and 7 feet becomes more like 2 degrees instead of 10. If I would shut the aeration system off for a week and I came back to check the temps and found that the pond was showing the 10 degree difference again (or close), I would assume that the thermocline had moved up the water column and the lower water had lost significant amounts of O2. I would hesitate to just turn on the aeration system without going through the typical start-up procedures.

Seems like the rule of thumb we might be looking for? - At least for an established aeration system with no toxicity issues at the bottom. A gassy smell would nullify the rule and demand the start-up procedures regardless of a small delta T.

An interesting observation I do a lot of snorkeling in my pond and before I started aeration not only could you feel the thermocline you could feel the difference in density of the water at the very bottom.

A buddy and I used to dive a quarry in East Tennessee years ago. It was probably 60 feet deep and gin clear. NOT only could you feel the difference in the water density, but you could literally see the thermocline. It was like looking thru some of that old wavy window glass.

In the ocean where fresh water meets salt water there will be a "halocline". The salt water being heavier and staying on the bottom and the fresh water being lighter and floating on top. In the few inches of mixing and transition is the halocline that is wavy looking like you describe. Kind of shimmering and fuzzy to look through.

You can see this many places along the Mexican Yucatan coast line where underground rivers dump into the Caribbean either by openings on the shallow ocean floor or coming out of lagoons.

It is possible the thermocline you saw could also have had some different chemical content causing some of the wavy look, although I suspect just the density of the cold vs warm water would do it also.

It is a very cool phenomena.

I'd give a lot of thought to just how much oxygen depleting stuff you have in those deep areas. What, besides your fish, could deplete the oxygen below the cool barrier...a lot of or very little organic sludge?

With only a 1/10 acre pond, adding good bacteria along with aeration and fountain, is an effective and economic option.

I find I'd venture to guess that an important point is that at which oxygen, from circulating water, meets bottom scum, that is working anaerobic digestion without oxygen, and starts to change the chemical process.

I am in the process of removing the muck from the bottom I use a 3" trash pump and a pvc pipe arrangement to suck the muck up and pump it to an above ground pool then I let it settle and drain the water back to my bait fish pond. The muck then gets dumped in to a pit to dry out. So I usually pump about 6000 gals out before I start the aeration back up.

If a pond generally has light penetration to its total depth is it also at risk of DO depletion? Also if shallow enough as to not have a thermocline does that make a difference on the need to aerate?

Even shallow water benefits from aeration. The addition of oxygen to the water serves to oxidize pond muck, bottom and circulating, with oxygen or aerobic bacteria. Oxidized muck generates CO2. Anaerobic digestion generates methane and hydrogen sulfide.

I started this thread with the opinion that some aeration, even if it is less than recommended amounts, is better than no aeration. I do not know that my opinion on that has changed, but I do have an observation over the last year that has shown me that inadequate aeration does have negative side effects. Or at least that is what I think I have learned. Who knows for sure based only on anecdotal evidence.

In the last few years in the heat of summer I have had some issues with bluegreen algae otherwise known as cyanobacteria. This was with aeration using three linear air pumps and three double diffusers in a three acre pond. The pumps were barely adequate to create decent air flow to the 8-10' depths encountered.

This year I installed a rotary vane pump GAST 1023 rotary vane pump upgrade installation to drive all three of the double diffusers with one pump. The single large pump puts out much, much more air than the three independent linear air pumps and subsequently I have put it on a timer and only run it 8-10 hours per day (kind of depending on the temperature and time of year - still an ongoing search for the best combination). This year I have had almost no problem with the bluegreen algae blooms. Till the other day. I was just starting to get some floating to my north shore line from a south wind. I kicked on the air pump and let it run 24-7. The visible algae bloom went away (probably mixed in) within hours.

It appears (anecdotal evidence only) that by increasing the aeration and water turn over it changed conditions to disfavor the bluegreen algae bloom.

I would be interested in others comments or experiences on this observation. It looks like to me I need to set my timer for a little more aeration in the current summer conditions. Also noteworthy is that we have had recent rains and new water flowing into the pond through the sediment pond which has a high nutrient load. So some new nutrient laden water could have been the cause of the bloom. At any rate increased aeration seems to have changed conditions enough to discourage the bluegreen algae bloom.

PBF get together September 22, 2018 SE Kansas

Since my aeration system is only weeks old, I haven't had much time to see just what kind of effect it has on BGA yet. I've had a phenomenal amount of fresh water coming into the pond this past week or so, all from runoff of my property as well as the neighbor's. So far, no negative influences.

I did increase the run time from 6 hours to 8 two days ago. Primarily due to all the cloud cover and lower surface temps. The only major change from adding more run time I've witnessed is the water is just slightly more cloudy. Whether from more bottom disturbance or the influx of this runoff, it's hard to say. I have noticed that with the water remaining more turbid, my FA has slowly gotten better.

It'll be interesting to see if it has any affect on BGA as time goes on.

Turbid water will definitely help with the filamentos algae. Anything that keeps light from reaching the bottom where it starts. Pond dye helps similarly.

snrub:

One thing that you touched on is the toxicity of the water when the aeration system isn't being run long enough.

Hydrogen Sulfide is the biggest culprit, and I will see if I can attach a link to an article that is geared towards aquaculture, but it could be applied to ponds. Here is an excerpt from that article:

The 96-hour lethal concentration 50 (LC50) values for
hydrogen sulfide to freshwater fish species range 20-50 μg/L,
and much lower concentrations stress fish and make them more
susceptible to disease. A measure of toxicity, LC50 reflects the
concentration of a compound in water that killed 50% of the test
animals in a specified period of time, e.g., 96-hour LC50.
Ideally, freshwater fish should not be exposed to more than 2
μg/L of hydrogen sulfide for long periods.

https://aquafishcrsp.oregonstate.edu › files › boyd2014hydrogensulfide_gaa

O.K. I don't know how to link to a pdf file, but if you copy the whole line above and paste it into google, the first hit that comes back is the article that I am referring to.

This will take ya there...

https://aquafishcrsp.oregonstate.edu/search/google/https%3A//aquafishcrsp.oregonstate.edu%20%E2%80%BA%20files%20%E2%80%BA%20boyd2014hydrogensulfide_gaa

NOT!
I tried esshup..

Let me try...

https://aquafishcrsp.oregonstate.edu/sit...sulfide_gaa.pdf

Thanks! That's it!!