Pond Boss Forums AERATION Should I aerate? Should I aerate all year?

Ive had my system on all year now but last winter I kinda missed ice fishing and ice skating
on my pond. What are the +s and -s of turning it off from Nov to March?...ct

Only one - in the winter. But it can be a big one if your pond isn't especially deep and infertile. It's winterkill or fish that are stressed enough to have disease problems in the spring. You may have to decide which is more important -- the ice skating -- or the fish.

However I don't open up the water completely in my ponds. Just one side. In fact, I have been told to create an open area off to the side and leave the deep central water alone as a santuary of slightly warmer water for warmwater fish. I had problems from stress from too thourough of a mix of the deepest water one winter.

Presently I run two diffusers in the summer an equal distance from each other and the shore but plan on putting in two more lines with diffusers closer to opposite shores to keep enough water open to prevent D.O. depletion but not mixing the deepest water.

Last summer I only used one diffuser in the center of the pond and then connected to a different airline and diffuser off to the side of pond under 6 feet of water once the lake began to ice over. I had no stress problems the following spring although it was a mild winter.

Aireation-- I'd love to but I cannot get power to the pond and right now the budget won't allow it.
I did have the DO tested yesterday at 7:00 a.m. at the 8 foot level off the end of one of the docks. The reading fluctuated between 7.20 and 7.35 even with a large amount of decaying vegatation and being at the end of summer with the water still pretty warm and tested early in the morning. As I understand it, that is a pretty good reading but that the DO will vary in different parts of the pond and at different times of the day. My questions is--is it necessary to test the DO during the winter months, even cutting a hole in the ice to do so? Are the necessary numbers the same during the colder weather or is less DO required?
Dan

It's not necessary to have power at the pond for diffuser type aeration. How far is it to the pond from your nearest power outlet? You can run an airline several hundred feet if necessary.

My questions is--is it necessary to test the DO during the winter months, even cutting a hole in the ice to do so? Are the necessary numbers the same during the colder weather or is less DO required?

It wouldn't be a bad idea and as long as D.O reading stay above 5 ppms you're fine. However you need to test in deeper water too.

If you set up a diffuser system correctly there would be no need to test D.O.

Thanks Cecil. The pond is approx 1/2 mile from the nearest power source. Too far to run a outlet or a air hose. I've checked into windmill punps but the low cfm bothers me. I plan on checking the DO again soon in the deepest part and other locations in the pond now that I've made contact with the person who monitors the water quality in the creeks and streams around the local mega dairy farms. I was surprised at the 7.35 DO reading and expected a lower reading partly because the pond has no inlet or outlet.
Dan

Dan,

That is good! Your best indication will be in late September before things cool off, and eventually the pond turns over, probably October (depending one where you are located.

I know this partly because we have lakes that are planted with trout in my area, and the the peak time of stress is in September when D.O. will be at it's lowest level for the year in the deep water. On one lake I've seen trout come up to the surface around Labor Day, but they become severely stressed and develop disease and fungus problems.

CT -- Some questions about your pond for some winter aeration answers.

1. How big is your pond? Answers from below: 3 acres

2. Max. depth? depth of majority of pond? Ans max 18' ave 9'

3. What is your fall weed and leaf input amounts? Ans max leaves

4. For your location in southern IN how long is your ice cover? Ans 3 maybe 4 months . Snow cover duration before occasional melt downs?

5. When you ice skate what percent of the surf area do you clean off? Ans 50%

6. What type/brand aerator do you have that you are running all the time? Air flow (CFM) and or horsepower? Ans. 1/4 hp, 4.2 cfm

Dan P. -- Diss. Oxy. Are they checking the oxygen with a probe/meter or chemical tests?
If using a probe, does it have a temperature read out? The pond's DO probably drops off at about 9-10 feet deep depending on water clarity.
The oxygen will usu. rapidly drop at the thermocline (where the temp. drops rapidly).

Have you ever seen the boil affects of a Koenders (Canadian) windmill? What is your pond's exposure to the wind? east west north south? Good exposure or sheltered? You have to have good wind exposure from three directions for the windmill to be really worth while..

Cicil-- I'm a little over an hour East of you and 12 miles North of Ohio. I will check the DO again later this month in the deeper parts of the pond. We checked at the 8 foot level as that was just off the bottom at the end of the dock.

Bill-- We used a probe/meter with a 25' probe. No temp readout.
The main part of the pond (957') runs East-West
and the prevailing winds are out of the West. However, there are woods on the South, West and North sides so it is pretty protected from "normal" winds. I've seen the ads for the windmills but have not seen one in operation.
Dan

Dan P. Since your pond is larger your stratificaion layer is probably at the 10-12 foot level; maybe 14 ft. Get your test person out in a boat to test for the depth of DO drop off. Once you find the thermocline, your DO will probably go from 7 to 3 in about one foot drop and from 3 to 1 or zero in the next foot. If you have DO of 4 to 6 down to 10-14 ft your pond can do pretty good without aeration. Extended (5-8wks) Heavy snow cover will be your biggest problem in winter. Removing snow is the best thing to minimize winter kill in areas with severe winters.

With so many trees and little wind exposure a windmill would be a very iffy investment. I live south of Adrian about 45 minutes. I sell windmills and air compressors for aeration. You are welcome to come and see both in operation. PS Come on a windy day. BC

Bill...
1. 3 acers
2. 9' average 18' max
3. max leaves
4. 3 maybe 4 months
5 1/2
6. 1/4hp 4.2cfm

CT- Pluses and minuses of running your aeration system IN WINTER in your specific pond situation.
Since your pond is fairly large with an maximum depth of 18 feet and your ice cover is usu 3 months (sometimes 4 mo.), I think you do not have to run your compresor during winter PROVIDING 30% to 50% of your snow cover is removed within 2 weeks of a snow fall. Snow cover for 3-4 weeks is now a point for concern for oxygen levels in your pond situation. DO situation near the bottom can be easily checked after 3-4wks of snow cover by fishing (see below). Oxygen is first lost at the bottom and then the decrease progresses upward from there. Since your pond has a lot of water volume due to the deepness 18 ft. the 'bank account' of dissolved oxygen is larger than say a pond 10 ft deep which would have less water volume and overall DO.

Snow is your enemy during winter. It limits light penetration thru the ice. Without light the phytoplankton cannot make oxygen and everything aerobic ('oxygen breathing' including plants) uses oxygen during darkness. In winter the oxygen is not consumed nearly as fast as it is during the warmest water periods. Three days of darkness in summer would probably be enough to kill fish.
Water under fresh/first ice cover has about twice as much oxygen in it as when the water is 80-85 deg. Thus it can last a lot longer before it gets to the point where the low levels are killing fish. How long the oxygen lasts is primarily dependant on how much dead material from autumn is still present to consume oxygen thru bacterial and benthic animal respiration which is quite low compared to summer levels but still measurable during cold water periods. Dead material in your case is primarily leaves which is a major concern. Leaf input amounts in relation to water volume is the most important factor for DO loss due to decomposition in your case.

After removing snow from ice in winter the phytoplankton can replentish the oxygen levels to saturation in about 8 - 10 hours of sunshine.

An easy way to check your oxygen levels near the bottom is to see if you can catch fish on or very close to the bottom. If you're catching fish near the bottom adequate oxygen is still there and aeration is not necessary.

Winter Aeration Negatives.
Cost of electric and wear & tear of compressor parts.
Aeration during very cold weather brings warmer bottom water to the surface and supercools it which causes more stress on your fish. The near bottom water has a little geothermal warmth to it and provides a slight warm water refuge for the fish providing oxygen is also present in this water. Disrupting or eliminating this refuge stresses them. Winter is the most stressful period for fish in the north. Aeration is not necesary if oxygen levels are adequate. Oxygen will be adequate if snow is removed (shoveled or wind blown) from 25% or greater of the pond surface; preferably lengthwise across the pond.
If snow cannot be removed from the ice the air flow from the compressor you have (4.2 cfm) and resultant bubbling can fairly quickly (10-16) hrs. open a hole in the ice (8" to 12" ice thickness) to allow light to rapidly stimulate oxygen production from phytoplankton. The open hole will increase depending on how much you run the compressor, amount of sunshine and the air temperature. The bubbling of the diffuser will also add some oxygen to the water but a small percentage compared to the oxygen produced by the phytoplankton. Oxygen production in the open water area and distribution of oxygenated water via the aerator currents should provide an oxygenated refuge during low oxygen lengthy, deep snow periods. Lengthy deep snow periods are probably rare in southern Indiana. Note this oxygenated refuge will be somewhat supercooled & the fish will probably seek the most comfortable location of temperature vs oxygenated water.

WOW !! Thanks a million. Im going to copy your reply and keep it handy. Lots of great info...CT

pond is in east texas..canton area . 3.5 acres 4to8 ft.deep.it is an old pond that is doin'g good . i have a lot of leaves in the fall, should i worry-?-i do not airiate..harvey

have 3.5 acre pond in east tx. lots of leaves in the fall . pond is 4 to 8 ft. deep . auto feed once daily, do not have an aeration system . this is an old pond but seems ok , have c-cat , bluegill, f-bass, just added crappie & threadfin shad,pond is spring fed most of the time.i have just started fertilizing..all the leaves should i worry about all the leaves ..harvey

Harvey,
That's a tough call. Lots of variables.
Aeration is almost always a good idea. But, it may not be necessary.
If you have a heavy load of organic matter, leaves, fish waste, silt...with little or no flushing during the year, aeration would be a good idea.
But, if organic input is minimal, and flushing is adequate, aeration isn't necessary.

Compared to past winters here in the Hudson Valley (NY), this years snowfall has certainly left its mark. With it comes my concern for the effects it may have on my fish.

Normally at this time of year I can count on the pond (60'x125'x8-10') being iced over, enough for skating and fishing, but the weather has been tossing us some real curve balls lately. A couple weeks back, we had rain and mild temps (hi 30's/low 40s) which weakened the ice enough to keep me off it. Temps have since returned to normal but a snowstorm on Christmas and one this past Friday has left us with 2'+ of white stuff.

I'm hoping that the runoff that's flowing into the pond will be enough to sustain the pond (in terms of DO) to prevent any winterkill.

Russ

Russ -- As Bob said above if you have a "heavy load of organics" in the bottom you need to be concerned. Since your pond is only 8' to 10' deep your water volume is less which means a lesser amount of overall DO in the pond. If you have quite a few fish in there plus the organics and 2' of snow cover it is black under the ice. NO photosynthesis. If you don't have a snow melt off by late Jan or Feb 01; if possible I would turn on the aerator to melt out a whole in the ice. Since snow can insulate, 2' of snow will prevent the ice from getting very thick even in cold temps. Be very caucious about getting on the ice to clear it of snow. Work a hole in the surface with the aerator; shouldn't take long since ice is not very thick & snow will melt quickly. Run it just enough every day or three to keep a hole open. It the hole freezes with clear ice, pump running is not necessary until snow cover reforms on top of the clear ice. Better safe than sorry.

Hey Bill.

Unfortunately I do not have an aeration system in the pond. However, I'm going to ask my neighbor if I can borrow her roof rake, which extends to 16 feet, and try to remove some snow load that way. Thanks.

Russ

Russ- Cleaning snow off ice around the edges in a small pond may get enough light penetration and DO production to get you by esp with thin ice.

With a pond only 8'-10' deep and likely occurrences of snow cover up to 1'-2' deep and if you do not want to lose fish you should invest in an aeration system esp for unusual years like this when you have thick snow before thick ice develops. Unless things change total loss of oxygen and major loss of fish will not usually occur in your pond until (guessing) around mid February. If you could aereate, you would want to do it before the deep water loses all its oxygen. Turning on an aerator during late stages of no DO in the bottom water will make the situation worse. As the bottom waters lose DO, fish move up in the water column for higher oxygen as winter progresses. When lots of deoxygenated water (anoxic) build up in the depths, and then you mix this water up & degrade the upper good water, fish will die. One should mix before the depths develop large amounts of deoxygenated water. This is why I recommended you turn on the aerator Feb 01 or end of Jan.

On the topic of aeration... it doesn't even have to cost you much to set-up a basic aeration system or to run it. A little tricky to get it going now with ice on.. but not impossible by any means. It takes very little air to open a good sized hole in even thick ice. A few dollars and a few hours work and you can save yourself a whole mess of trouble. Much easier to plug in an extension cord then it is to keep clearing snow... and even when you do depending on how the ice formed you might not get as much light penetration as you would like.

With the help of my neighbor's snowblower, I made time this weekend to clear the pond of the remnants of our last two major snowstorms. With a snowfall of over 2 feet from these storms, I was very surprised to find that the snowload on the pond only amounted to 3-4 inches. Once cleared, I augered a number of holes to check ice thickness. Total thickness was 11 inches with the top 7-8 being, what I've heard referred to as, snow ice. Although it appeared stable in structure, it had the consistency of a flaky pie crust. The remaining 3-4 inches of ice was clear.

With clear ice being the optimum for light penetration, I'm curious to know what effect "snow ice" has on light penetration?

Lastly, for those interested, we did get in some fishing time. My neighbor took the honors today landing a 14" smallmouth....twice! Once on land and the second time in the frying pan.

Russ

I would think it has more light penetration than snow and less then clear ice. Catching any fish close to bottom in the deepest water? If so, oxygen levels are still fine. (Thanks Bill Cody for that common sense tip).

I went out to my pond yesterday and couldn't keep the jumbo perch off the hook. They weren't monsters but were chunky 11 1/2 inch females (don't have any males in the pond as I planted with close to 100 8 inch females last spring). I hope to grow them to 14 or more inches!

Russ - Glad to hear you were able to get snow off the ice. Cloudy ice 7-8" thick is allowing about 20%-30% of the light to pass thru. Still enough light transmission for photosynthesis.

Was the water clear that you fished in?
If so light was able to penetreate into the water fairly deep. With this much ice and more forming daily with this cold wave; it will be important to not let snow cover lay very long on the ice. Sooner you can get it off the better oxygen levels will be in the pond.
As Cecil said above, as long as you can catch fish near the bottom, deep water conditions are healthy.

Cecil and Bill,

In addition to drilling the holes to check ice thickness, I also wanted to check pond depth. Its been 7 years since the pond was excavated. In all the holes I checked, pond depth has decreased about 0.5 feet. I'd like to think the desilting pool I made upstream of the inlet is serving its purpose.

Cecil, we were fishing 1-2 feet from pond bottom.

Bill, the pond water is clear but very dark. I have a number of swamp white oak trees that ring the pond and the leaves make for some very dark water. The game plan is to clear out some of these oaks to help cut down on the volume of leaves that enter the pond.

Russ

I am not real familiar with phytoplankton types and their densities in tannin stained water. Degree of stain undoubtedly has a big impact here.