Pond Boss Forums INTRO Questions & Observations Aeration "Supercooling"

RobertB, My understanding is that all biological processes involve liberation of heat energy so I'm sure you're correct in your "composting" suggestion.

Russ, I'm glad nobody thought of your idea when I was in school. I might still be in graduate studies.

Russ/Bruce: Now I'll have to decide between the dark brews and the light domestic brews. Which will most motivate?? Questions, questions, questions.

Dave

Dave,

Dark or light domestic....you're getting into the deep water now. Since I don't drink, I'll have to step aside and let someone else toss you the life preserver.
:p

Russ

After reading through this thread and using my personal experiences of this past winter, it is readily apparent that clearing the snow off of the ice is extremely important to the survival of fish populations in smaller ponds.

My pond is 2/3 the size of a hockey rink and has a max depth of 25'. I cleared the snow off for pond hockey every winter and noted that one or two bass has died off, in seven years. This past winter was crummy with heavy snowfall followed by freezing rain and slushy conditions that made the chore of clearing the pond less than appealing. Couple that with the risk of taking the new heavier snow-thrower on thin ice and a general laziness on my part... well, it just didn't happen, OKAY! Sorry.

You can guess the rest of the story, I am sure. We were horrified to find a complete annihilation of our beloved smallmouth bass. Not one survived. My son and I counted 42 fish floating or visible on the incline around the sides. How many were on the bottom out of view?

My name is AZ, and I am a fish killer. I am here to get help.

We drag the diffuser into the area around the overflow just to keep it open when the pond freezes.The swans and geese and deer seem to appreciate it; we haven't lost any fish to date but if anyone thinks the HSB would prefer no aeration in my zone this winter, please let me know.

I see that AZ has found this thread just like I just did. AZ you asked some questions on another thread about this subject and I replied with my limited experience. This appears to be the place to be. As I indicated in that thread I was aware of the issue with super cooling and with the belief that fish were also unable to absorb oxygen if they were stuck in water that was too cold. That is what an expert told me. Whatever the case is I have been successful with HBG, LMB, and crappie in my 1/2 acre pond with bottom air stone diffuser (deepest part of pond) that runs as much as possible in winter to keep the DO level up but not so much as to drive the water temperature too cold. It appears putting the aerator in the deepest area might be a mistake but its worked so far. My rationale was to avoid stratification and give the fish more area to live in. I keep thinking that one of these days something I've done wrong will catch up to me and I'll lose everything but I can't bring myself to change something that's been working. I can't afford a DO meter so I calculated the size of pump and number of stones required to result in a DO much higher than my calculated BOD.

Hope you guys don't mind me interrupting your technical discussion with a funny story about winter aeration? I just gotta tell this to somebody! Last winter I figured it would be kind of fun to experiment to see how long it took to open a hole in the ice with the aerator. So I turned the air pump off one evening so that the pond could freeze over night. The next day I had about 4 inches of ice over the whole pond. My pond is oval shaped. I turned the aerator on that morning to see how fast I could melt a hole. There was no snow on the iced and the ice was crystal clear. To my surprise before the moving water under the ice could melt a hole the ice lifted up off the water. I let the pump run for about 6 hours and it continued to blow up my pond. The ice lifted up over a foot above the water like a big balloon, my air gage said I had 5 psi under the ice. I kept thinking it would eventually break. It didn't melt cause the water bubbling upward no longer touched the ice. This went on until the entire pond all the way to the edges had a ice dome over it. I finally got tired of waiting for it to break so I got the 22 rifle. One shot in the middle of the pond and the whole thing exploded into a million pieces. It broke so violently that I got all wet standing by the pond. When my wife asked what happened I told her I "blew up the pond". She's still confused. Should start a thread on pond stories.

bz - did you get a picture of the ice dome?. Home video would have been even better; it might have got you on a TV show.

Bill, wish I had a picture. Now that I think about it I must have had the aerator running all day cause I started it in the morning and didn't blow the think until after dark. I have a yard light shining on the pond but that wasn't enough for a picture. If I had known it was going to be such a show I would have at least tried. Always wanted to send something to Funniest Home Videos. Had another incident last winter where pond froze over despite the aerator, -20 F will do that. It took a shotgun slug to break through this time but is wasn't good solid clear ice so it didn't shatter. When the ice dome dopped back down onto the water a geyser shot up out of the 3 inch hole and got me right in the face from about 15 feet away.

bz - This winter's ice follies may provide material for some pictures.

I got my airstone moved to shallow (3' or 4') water today for the Winter, for the first time. I should have done it last weekend; we had 1" of ice on the pond the day after Thanksgiving, which fortunately had almost all melted today. Water temps were 40.0 deg F at the surface and 39.6 deg F on the bottom.

My wife assisted from shore and came up with the great idea of floating the 5 gallon bucket with gravel and the airstone using (swimming pool) noodles. I could fit 3 noodles through the handle on the bucket which provided plenty of floatation, making the job much, much nicer to accomplish from a canoe.

Re Aeration: Have 1 acre pond, 15 yrs old, stocked for 4 years in E. Central Ia. The 1st 3 years after stocking simply put a large round bale in at shore edge before freezeup. Had no problems with winterkill. Did not break ice nor remove snow. Last year I got "professional" and installed a 1/2 horse Gast "fin" pump, 1/2" tube and stainless steel diffuser in deep water. Created a 15-20' hole in 8" of ice all winter. This spring I had fish kill (LMB, HBG, couple of CC). Needless to say I now have a cheap big bale of grasshay at the pond edge. We'll see what happens come spring. Thanks-Postbeetle.

Thakns for the information, postbeetle! Quite a few of us are trying to better understand winter aeration. Did you have your airstone/diffuser in the deepest water in your pond?

Well Postbettle from my experience you over did it. I did the same with two airlines in deepwater a few years ago with a 1/3 hp compressor. I had a partial fish kill too come spring along with stressed bass.

I now use a much smaller compressor and airflow to the lip edge of the ponds. No more than three feet deep. I believe I could get away with no air flow if I keep snow of the ponds (do that too), but the problem is there is always a chance you could get thin ice with a heavy snowfall and not be able to get on the ice to remove the snow. I also go to Florida to visit the folks a few weeks in December every other year, and don't want to take the chance of heavy snowfall while I'm away.

I'm going to set up my smaller compressors and airlines today.

Dave :

I just revisited this post and was interested in an update on the status of the ponds that were in the works from last Dec. Were they built, how many, size, cost , use , etc.?

Ewest -- I assume you are referring to the research ponds? No progress on that topic whatsoever! However, we definitely hit a cold spell here after a nice, long, warm fall. So, I probably need to start thinking about some D.O. profiles on a couple of the ponds. I'll bet we can get out on some ice soon. The 7-day forecast calls for below-normal temperatures.

post, I believe Cecil has your answer as to what may have gone wrong.Winter aeration can be quite simple and complicated at the same time. When trying to find and maintain the balance of a high percentage of DO saturation and water temps not stressful or lethal to fish without a DO meter it is difficult.I find most winter aeration overdone in the midwest.When your BOD is very high winter aeration is more critical and with a low BOD it may not be needed at all.When in doubt and no way to tell the DO level just keep the snow off of at least 20% of the surface and chances are you will be fine. This is my preferred method. Next method is to have a seperate diffuser (or move your exsisting one) to the shallows and only run when snow cover is present and only as long as it takes to melt off an open area and them let refreeze clear.On ponds where multiple diffusers are present shutting down the majority of them and using one designated as the winter diffuser works too. Caution if you have more CFM going to that one diffuser than it can handle.Either vent off so that you have 1-2 PSI going to that diffuser or install a diffuser that can handle variable CFM (look at the AirPod from Aeration Technologies Inc) as it can take from .5 to 10 CFM.Lastly if you have your only diffuser in the deeper part of the pond and cant move it and cant install a seperate winter diffuser then consider at least venting off most of the air to it, say 1-2 PSI and slow it down. The idea of large open water so a pond can gass off often supercools the bottom of small ponds (8-10 acres and less) and does more harm than good.Winter is already the tough time for fish and over circulation only makes things worse.Most 40F water that is 80-90 % saturated has 10-12 ppm DO in it already and that is twice as much O2 as you need this time of year.Many of todays diffusers can circulate over 4000 GPM with only 1 cfm (20 ft of water)and your pump may have over 4 cfm available.Since proper winter aeration differs so much from year to year I would stay on the conservative side in a small pond.If you have 20 ft or less depth in a 1 acre pond and have open water all winter from aeration and air temps single digits and below you probably have your bottom water too cold (less than 39F) If you have one or two diffusers (depending on depth) running in a 8-10 acre pond all winter probably will not cause any problems as its the smaller ponds that are the most difficult to manage.Use the ice to your advanage as insulation against the super cold temps. Good Luck.