Pond Boss Forums AERATION Systems questions Advice on aeration needed

Hello Pond Boss Members,

I had a quick question I was hoping to get some help with. The level of expertise on this site is staggering so I am sure that I with your help I will be able to make an informed decision rather than just guessing. I have a small (1/2) acre pond I am looking to aerate. The pond is roughly a square and runs from 3 feet on the shallow end to roughly 15 feet at the deep end. My question is will a fountain with a draw tube prove to be effective at aeration and destratification or should I solely be looking at bottom diffuser systems? I have tried researching this topic on this site and have found a lot of good guidance, I just haven't seen the benefits of the two systems compared. Any advice or thoughts offered will be greatly appreciated.

Thanks,
Chris

Hi Chris - I think I understand your question? Answer will depend on A. how long the draw tube is, b. size of motor, C. how long each day it is operaterated, D. temperature of the water, and probably a few other things such as exposure of pond to wind action. If one extends the draw tube to within 2-32 ft of the pond bottom a fountain will do a better job of mixing that pond. However a bottom bubbler will do an overall better job at turning over a deep pond than a fountain ever will,not matter how long the draw tube is. However if one want pretty, splashing water, and aestetics then a fountain wins the game.

First thing to remember is a fountain lifts and throws water into the air. Water is heavy (8 lbs/gal 5 gal weighs 40 lbs) thus very expensive in electricity / energy to do this vs moving and compressing light weight air to do the work of moving the water. The higher you throw water the more it costs. I'm not a fluid dynamics expert, but I think that just pumping, moving and lifting water is not very energy efficient compared to compressing, moving air. In terms of energy efficiency of moving gallons of water per hp & killowatts bottom aeration for moving water is very cheap compared to fontains.

Here are things to read for homework on this topic:

Which Way - Fountain vs bottom
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=29965#Post29965

Fountain or Bottom
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=30521#Post30521
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=150329#Post150329

Pump types
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=30070#Post30070

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=30075#Post30075


Confused about Aeration
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=30388#Post30388

Homemade fountain
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=30223#Post30223

Lengthy discussion from the Q&A Archives about various types or aeration andbenefits and concerns.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=92494#Post92494

Bill:

An easy way to figure the price difference (operational costs) is to look at how many gallons per hour lifting rate a diffuser (pick a certain one) has. Now figure out how many diffusers could be run from a 1/2 or 3/4 hp compressor, that will give you how many gallons it'll move in "X" time. Compare that to a water pump that will move the same amount of water in the same amount of time.

I am a Master Plumber and pretty sharp on figuring out just about anything. To me it seems pretty easy to hook up a air compresser pipe it to the deep water drill holes in a pvc pipe and blow some air. Whats so hard about that? I have read for weeks about stocking my pond. My pond is about 1.5 ackers and it is 25 feet deep. Should I blow air in the bottom and if so will this stop pond turn over? I will be buying my fish from overton next week. stocking 8 inch blues and stripes fatheads red ear and shiners. how long does it take to eatting sizes

plummer - that is one way to do it. As in plumbing there are different ways to do it,,, some better than others. Why use 3/8" pipe for a house or shop when 1" was needed? If you are going to do it why not do it the best way to get the most benefit for time and effort rather than 1/2 way and get less efficiency for your electrical dollar plus maybe having to redo it later?

Aerating if sized properly maintains pond turnover all the time the aerator is operating. Your goal should be a minimum of one complete pond turnover (total gallons) per day. Each aeration unit depending on design has a turnover rating; similar to water pumps have flow ratings. The quicker you can do a turnover the less the unit has to operate.

Time to get eating sizes of fish depends on how big you consider eating sizes foe each species.

What is the effect if you can't turn your pond over once a day?

How do I size the aerator? I thought about sinking a 1 inch pvc pipe 20 feet long drilling several holes in it piping a tube to it attaching it to a compressor and installing a regulator and let it do its thing for several hours each evening. I never thought about aerating it I assumed it had deep water it was good but after reading about ponds because I want to stock it I found deep isnt better. My pond is 25 feet deep I dont want my fish to run out of oxygen. I want a good fishing pond and am trying to learn the dos and donts

There are many effects of turning over a pond once a day. A few of them are:
1. warmer temperatures at the bottom to a point of even temperature top to bottom depending on aerator run time.
2. no thermocline, nor anoxic hypolimnion.
3. adequate oxygen for life forms in the bottom waters in late spring through late fall.
4. bugs and worms (fish foods) now living in the belly of the pond that used to stratify in the summer and was void of any regular living fish foods (bugs) at or near the bottom in the pond belly.
5. no build up of noxous toxic gases methane and hydrogen sulfide in the deep water zone of the pond.
6. Faster, cleaner decomposition of organics and muck in the pond's belly.
7. pH of water in the the pond belly is no longer acidic during the summer.
8. Water often becomes overall clearer but not guaranteed. This depends on each pond's unique condition.
9. More pounds of fish will be raised in the pond on natural foods and with pellets.
10. Natural oxygen production will be greater in the entire pond compared to pre aeration.
11. Chance of a fish kill is significantly less.
12. Fish are said to be healthier but not a lot of data are available to prove this.
13. Clearer water may result in more rooted vegetation growing on the bottom.
14. It will cost the owner some money to operate the aerator daily even if it is a windmill - depreciation cost and maintainence -rebuilds.
15. Overall better water quality during the summer.
16. The trend is toward fewer bad algae (Cyanobacteria) and more good algae types (Chlorophyta, diatoms, chrysophytes, cryptomonads).
17. Fewer and less amounts of algae surface scums.
18. Better distribution of any chemical applications top to bottom.
19. Fish can utilize the deep water structure during the summer in the pond belly.
20. It lowers the annual total natural dissolved phosphorus budget within the pond.
21. It increases the useful life span of the pond before it becomes a mucky, swampy, weedy wetland. In other words is slows the natural succession process.

To properly size an aerator one has to know the water flow rate or up welling flow (lifting rate) produced by the diffuser. Generally the homemade diffusers are not as efficient as the commercial ones that are specially engineered and designed to produce maximum flow using the least amount of air volume. It is hard to calculate the flow rate of homemade diffusers but one can come close to the flow estimate if one knows all the components. Depth of the diffuser also plays a role in flow volume. Calculating aerator flow is sort of similar as calculating fluid flow rate through a pipe - one has to know all the variables.

The general rule of thumb that I start with for clients is the smaller you make the bubbles and the more bubbles you make the more the flow. Next. Too small of bubbles (pores) from the wrong type of surface material tends to allow the pores to clog more quickly - it depends. Air released from an underwater pore tends to accumulate or collect solids in the pore from dissolved solids such as lime and minerals (iron) in the water. The accumulating solids allow for various types of bacterial and slime growths in the pore dispite air flowing through the pore. I don't know the academic reason this happens but it does.

If one lives in Texas or almost anywhere in the US and the pond is 1 ac or less the water deeper in the summer does not mix naturally deeper than 6-8ft deep. This depends but generally is correct for many sized ponds. All one has to do is measure the temperature of the water at the surface and temperature at 6 ft and 8ft and bottom. Any difference in temperature from surface and deeper greater than 6F indicates the surface water is not mixing to that depth.

would it not be better to have a pipe 20 feet long distrubating air verses a 8 inch defuser? seems to me that 20 feet of water moving will turn the water quicker. when is the best time to aerate or do I have to run it all the time. is a ecoplus 7 pump big enough for my pond

I learned this rule first when studying homemade aeration. If drilled pipe does not lie perfectly flat once the air reaches the holes all the air will tend come out the first several holes and flow will not move very much farther down the pipe. The deeper the pipe is the more this rule applies. Test it and prove it to yourself. This also applies to square or rectangular shapes made from drilled pipe.

I can see that the pores clogging up with build up. so I will get a defuser. I know my water does not mix because we swim in it and it is warm on top and go down about 10 to 12 feet and it is very cold. so when do I need to turn it over and do I run pump short periods when I start making it a little longer each day. do I have to run pump all the time? and do I just worry about summer months

Bill, I appreciate your answer on a complete turnover each day. We had our front pond sized to do this but it takes 10k to do it. We don't live there and are afraid of someone stealing the 4 3/4h.p. compressors. Would it be O.K. to turn over 1/4 of the pond each day. The pond has about 40 million gallons.

How big is that pond ken? They don't recommend partially aerating a pond.

You should buy your sister a gift subscription to Pond Boss magazine - Birthday, Chrismas, Valentines day or just because you love her and use her pond,,, being you are the good brother you are.
http://www.pondboss.com/subscribe.asp

Or you get the subscription and give her your copies after reading and learning. Currrent issue Mar-Apr 2013 talks about aeration start up time. Lots of variables about aeration specifics in your sister's, yours or anyone's situation. If you go by the advice of most professionals they will say run it all the time and this is more true the further south (warmer) your pond location. Generally start running the aerator when water temperatures reach 50F and stop with they reach 50F in the fall - exceptions to this rule occur. IMO if one is concerned about running 24/7 then it is better to run one longer period compared to two or several times per day because the longer run time results in a more complete pond turnover. This general rule applies ONLY if the aerator can turn over the pond several times a day. If the aerator cannot achieve one turnover a day then 24/7 aeration is generally the rule to follow.

BGK, I sent you a PM.

I did some figuring and come up with almost 7 million gallons of water in my pond that was over measuring it LxWxD and multiplying that by 7.5 came up with the pump I was looking at is way to small. So the best thing for me to do for my pond is to turn it over daily

If your pond is 25 ft deep make sure if the diffuser is in the bottom of the belly the pump has at least a 15psi or 30 psi model is better which provides a little psi 'buffer' for piping, distance,and back pressure due to diffuser clogging.

If I had a pond is as big as 40 million gallons, I would do a stratification survey plotting DO, temperature, and depth contours. A good aquatic ecologist would then look at biochemical oxygen demand, water shed fertility, nutrient budgets & status, productivity and then be able to determine if a complete calculated turnover was needed, if aeration was even needed, and best how to manage this water body.

I plan on buying a pump and a defuser piping it all myself I dont want to spend thousands. If it doesn't turn over the whole thing in one day it still should mix the water. How critical is daily turn over. Do I need to start mixing on a short time period amounts to keep from contaminating my top layer and killing all my fish. I am sure my bottom layer is much greater than top.

YP, When you visit Todd Overton ask him about either a Vertex Air One Plus or Air One XL depending on the length and width. You are looking for a minimum of 4861 GPM system. The lifting rate is important but spacing (placement) of the air station (s) is critical also. If your pond is 20 ft deep and 300 ft long and 200 ft wide placing a 4 head station in the center will provide the same lift as a pair of 2 heads spaced 100 ft apart mathmatically speaking.In reality you will have more vertical current on the 4 head area than using the pair,so to affect all of your gallons in this example you may be better off with a pair of stations using the same small 2.5 cfm compressor.Todd can size you the proper system.

Quote: "I am sure my bottom layer is much greater than top." Do you mean volume of water as "bottom layer"? If yes, then this is rare in most bodies of water especially ponds. One does not really know the size/volume of the bottom layer unless the depth of the thermocline is known, plus other items. Why is your pond unique or different than most? Do you have a depth contour map of your pond? Or do you know the average depth? What is the shape of the pond? Shape and to a lesser extent depth determines how many diffusers one needs for producing turnovers. What type of air compressor/s are you planning to use?

Daily turnover does not become as critical in certain pond situations - less critical for aeration are those with lower productivities, (lower nutritent inputs) such as mesotrophic or oligotrophic (nutrient poor waters). Very clear water ponds (secchi disk readings ranging from 6ft-10ft) also have less need for aeration. The more enriched a pond is the more the need for turnovers and oxygenated bottom waters to minimize oxygen depleated conditions - anoxic - anaerobic. Fertilizing a pond increases the need for aeration if water quality is important. Of course if one does not care if the pond ages prematurely and lower water quality occurs more frequently as time passes then there is no need for aeration. Mother nature will do what she normally does - age your pond at her pace based on the surrounding conditions.

Bill, I am going to get Travis to post pictures of my ponds as I can't. The only thing I am worried about is fish kills. The ponds are gravel pits less then 15 y.o. so aging doesn't concern me.

Ok I dug my pond over 8 years ago and pumped it out and redug it during the drought it shape is like the hookum horns if you google map 14420 forest circle east montgomery tx you will see the shape better. You can see the end of one finger the other finger goes back in the woods another 200 feet that is a natural ditch about 30 feet wide and about 15 feet deep. I left this natural for fish habbitate. The banks are very steep wal out 3 feet and its over your head. The whole lake that you can see has a flat bottom and atleast 20 feet deep. I shot the bottom with a laser and it is pretty flat. Now I read good fish water in in the first 6 feet well I have about 18 feet of water below that that is not mixing. I know it isn't because we swim in it and it is warm on surface and 10 or so feet down it is freezing. Thats my concern about mixing my water. I am not sure what pump I need yet.

Now my pond has good color and sandy soil on top of the clay when swimming you can see your hands below water almost 2 feet deep

Ok I dug my pond over 8 years ago and pumped it out and redug it during the drought it shape is like the hookum horns if you google map 14420 forest circle east montgomery tx you will see the shape better. You can see the end of one finger the other finger goes back in the woods another 200 feet that is a natural ditch about 30 feet wide and about 15 feet deep. I left this natural for fish habbitate. The banks are very steep wal out 3 feet and its over your head. The whole lake that you can see has a flat bottom and atleast 20 feet deep. I shot the bottom with a laser and it is pretty flat. Now I read good fish water in in the first 6 feet well I have about 18 feet of water below that that is not mixing. I know it isn't because we swim in it and it is warm on surface and 10 or so feet down it is freezing. Thats my concern about mixing my water. I am not sure what pump I need yet.