Pond Boss Forums AERATION Should I aerate? Winter Aeration In Northern Canada

I live in Northern Manitoba, Canada and I have a pond approx. 150 feet long x 100 feet wide. In the deep end which comprises approx. half of the pond the water depth is normally 10 feet deep the shallow end is approx 4 to 5 feet deep. My property is all sand and gravel and it has been a real dry year and at present the pond is 7 to 8 feet deep at the deepest spot and 4 to 5 feet deep in middle. The pond is 3 years old .

.I have approx 300 rainbow trout that I stocked in early April this year they are approx. 1 lb now.

I have a home built aeration system at the edge of the pond with 2 air stations with 2 - 9 " rubber membrane diffusers mounted on each .The compressor is mounted in a vented enclosure.

Since it normally gets very cold here in the winter , some times -40 Celsius plus , I am concerned with my current water depth that without aeration the fish could die through the winter. I have the following questions that would be much appreciated .

- what is the best diffuser location for winter aeration and depth?
- should I run both air stations or only 1 ?
- how long should I be running the aeration system for during winter 24/ 7 ?
- is it necessary to add check valves at the air diffuser when using EDI -" Flex air diffusers" or is the internal check valve enough?
- I have 1/2" poly line to run to diffusers , is this sufficient for winter use?
- what is the best way to set this up so the lines don't freeze during the winter ?

any info would be much appreciated

I just shut down our system for the winter here in the Catskills of NY. We are full and have some runoff. Their has been several killing frost night and I decided that was it for the season as far as aeration goes. Will start it up again when ice melts in March.

I seem to be the only one around who runs aerators all winter. I'm in Minnesota which is nothing like Manitoba but definitely colder than our friends in Texas. I believe my aerator has helped keep my fish going all winter because I'm not always able to keep snow off the pond. But I only run the aerator for two 4 hours shifts per day and I think the effect is more along the lines of keeping an area open so that the sun can get through more than adding air. It seems to be the consensus on this forum that if you can keep the snow off you don't need aeration. So far I haven't had the guts to turn my system off since my fish have done well for 3 years before anyone told me I shouldn't use it. My diffusers are also in the deepest water which I'm also told I shouldn't do. I will say in support of the idea that you don't need aeration is that I have a pond with two distinct sections (8 feet and 6 feet depths) separated by a long narrow channel. I have bottom diffusers in both sections but I only run the one in the deeper section during the winter because my family skates on the shallower section. So I plow the shallow section whenever I can. I discovered last year via fishing and with a underwater camera that my fish appear to all move to the shallower non-aerated section of my pond during the winter. I had thought it would be the opposite. So I believe that the aerated section may be getting too cold for the fish and the non-aerated section obviously has enough O2 in it because I've never lost any fish due to winter kill. So, all that said, I tend to believe you don't need to aerate if you keep the snow off but I still don't have the guts to turn mine off completely. I'm just going to keep doing the same thing that's worked. Signed, Still confused!

Wood in Alberta is probably our best expert on really thick ice. He gets something like 2 to 4 feet. IIRC he does not aerate at all in the Winter, but keeps enough ice clear instead. Of course he's out on it all the time, I honestly believe he can ice fish like 5 months a year.

Maximum - You need to read all of Wood's posts regardijng his trout pond in northern Canada. I do not have time now to search for them for you but maybe someone else can help. I will check back Wednesday and help out if necessary.

Start with those on the list at this link. If not there - post back and I will try to help.

http://www.pondboss.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=recent_user_posts;u=00000349;filter=topics

Maximum - There is a lot of previous discussion here regarding winter aeration. Here is just one link that discusses it. However keep in mind the climate where you live compared to comments from others who live in areas with milder winters.

http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=20;t=001274

Please come back here and let us hear about your efforts with winter aeration so your experiences can provide more information to those with ponds during harsh winters. Thanks for using Pond Boss.


A forum member - Wood - also lives in an area with similar winter conditions to yours. Here is a copy of his testimonies regarding his experiences with trout in a small Canadian pond.

CODY SAYS - Aeration can increase the chance of open water during ice cover that allows sunlight penetration and microscopic and or benthic plant activity. Snow removal from the pond produces the same benefit. A PB forum member WOOD proved that snow removal was adequate for a northern Canada trout pond with 3 ft of ice cover during winter of 2004-05. See his testimonies below.


WOOD SAYS - I can share what has been working for me, I won't call it advice, as I am still learning also. Air pumped into your pond contains about 20% oxygen. Air produced by plants and planktons is near 100% oxygen I believe. My trout have successfully wintered two years now with 200 days of ice cover, max ice thickness 37" with seven feet of water below. No aeration, but I removed snow cover within a few days of new snowfall on about 3/4 of the pond. I tried to aerate two winters ago and had problems with airlines freezing (see items below for his problems) . Lower fish densities probably helped with keeping DO levels up also. Most ponds around me do not use diffusers in winter, either nothing or top water splashers.

I just managed to remove snow yesterday, took three hours of plowing just to get the truck to the pond. I plowed most of it to one end, then drilled a number of holes close to the piles. The weight of the snow forced water out the holes for most of the day. Instant skating rink. I also dropped the camera down and found the fish alive and well. I will not start up aeration until around May.

Bill, as proof to your comments on light penetration, I have seen a significant increase in the trout's activity level since removing snow. I watched their movements before and was shocked at how lethargic they were and also how the fishing has improved since plowing. I fish many more days on ice than open water and we do become very familiar with ice conditions and types. I currently have 37" of ice and considering the water level was down to about 10 feet before freeze-up, only leaves 7 feet of water. Trout are pretty resilient I'd say.

Wood goes on to comment after his first winter experiences, that after trying to maintain aeration through last winter and dealing with frozen airlines, I have decided not to aerate at all this winter. We also skate, ice fish and DRIVE vehicles on the pond and would not risk an accident with thin ice. I will shut down the compressor at first ice, early October and will re-start when ice is completely off, April or May usually. I plan to remove snow from two-thirds of surface once it is safe to walk on and keep it free of snow. I had no fish kill doing this last winter with ice thickness of 36". I did not change my compressor run times at spring startup, 6pm to 8am and my pond did not stratify this year. For me at least, snow removal is more important than winter aeration.


You make a valid point regarding the impact of BOD on whether winter aeration is necessary, and I do not know the answer in your specific instance. I did over-winter trout for two years successfully with only snow removal (and lots of it). My pond is less than a quarter acre with around a 100 trout from 12" to 16" at that time. My pond is also only about three years old which I believe helped. I did get around 200 days of ice cover and no fish kill.

I have since moved my family north and have rented my property (and pond) to a young couple. The husband seemed quite enthusiastic about fishing and pond maintenance. Last winter he was instructed to remove snow as part of the "deal" if he wanted to have fish to catch. I realize you do not want to experiment and risk loosing your fish, but it did work for me.


Trout Status - I measure water temps and have noted that this year with my aerator setup (open water operation), my pond remained de-stratified all summer vs last year without aeration. I raise trout and find them at all depths including bottom. So I can tell you I have both adequate DO and turnover, but I don't measure how much.


PUMPS -The 1532 would easily mix your pond. I have a Gast diaphragm compressor, .9 cfm at 10 psi. I run 300 feet of 1/2" poly connected to a weighted garden soaker hose. My pond is a little larger than yours and my Rainbows did well through a hot dry summer. I ran it 24/7 until the heat of summer and then only when air temps were cooler than the water temp, usually at night or cool cloudy days. Since I have trout, I have to be careful with warming the water and my system easily de-stratified my small pond. The $40 price tag is too good to pass up. 3/4" black poly water line is cheap as is the soaker hose. Should work excellent for you. Btw, the soaker hose idea was from Bob Koerber, some time ago. This may not apply to you, but it didn't create enough surface boil to keep an area ice free this winter. No suprise for me.

I use a Gast diaphragm compressor, .9cfm, 1/8 hp. 300 feet of 1/2" poly run to the pond. Diffusor at 13 feet deep. My pond is small also, 180ft x 50ft. I run for 12 hours nightly till freeze up. It's been two years, trouble free, except for frozen airlines when I tried to run through last winter. This unit will handle higher psi than vane style.

WINTER AIRLINE TROUBLES –
I have 300 feet of 1/2" poly airline running to my pond. It froze up once in December after a warm spell, temps went from -30c to +5c then back down again. I imagine there was condensation from the swing in temperature. I dragged it out of the snow and cut off about 250 feet and brought it in the house to thaw. I then blew it out with the shop compressor, put in a little methyl hydrate, re-connected and everything was fine.
About two weeks ago it froze again. Temps have been reaching -40 here for awhile now, so I have not bothered with it. It's enough trouble keeping vehicles running and commuting to work every day. We also just got a huge dump of snow and now there is over two feet on the pond, which I'll plow off with the 4x4 this weekend to let some light through.
I did not bury the airline originally as the frost line is more than four feet down. Water lines here are at eight feet otherwise they will freeze.
The compressor is unheated under my home. Airline is downhill to pond. I think any moisture freezes before it has a chance to drain down and the i.d. gets smaller until blocked totally.I think rather than trenching airline, I will trench power instead, as it would be handy at the pond anyway. Next summer's project I guess. Dave, +5c in December is highly unusual here and felt quite warm indeed. Cecil, ice came off lakes last year on May 24th. Ice on my pond is well over 30" currently. Almost half way to spring now.
The airline was frozen in two places, one about 75 feet from the compressor and also about 50 feet ahead of where it enters the pond. Robert B's comment regarding splices makes sense and I think a larger i.d airline may also help my situation. Norm's 4" pvc pipe idea is also good, I will use this next winter. I think I will end up putting power at the pond next summer to eliminate this whole problem. I would like it simple and hassle free, at 40 below, you just can't be messing with stuff, skin freezes quickly.
Aerator has been shut down for a month now and temps are up again to just below freezing. We got dumped on again, snow is almost three feet deep.

Bill and guys thanks for all the feedback , I will do some more reading on Wood's experiences. I am still thinking that due to the depth of my pond, I may run 1 aerator in the shallow end , and even turn on the aerator in the deep end once and a while through the winter.

I am still concerned about the airlines as they enter the pond, currently my lines enter the shallow end of the pond on the ground as the compressor is located on the edge of the pond. Will the black poly line handle the pressure of the ice forming around it without busting ?

I think I have a work around the moisture problem in the lines . I am going to install a desiccant air dryer that uses the pellets to absorb moisture installed after the compressor inline before the air enters the poly pipe going under the ice. These things are cheap and also easy to make.

Any thoughts on this ? Thanks again for all the help.

Maximum - We are very interested in how your ideas and plans work out. Please keep us advised as winer progresses.

Maximum, appears you are getting some great feedback.Let me add my 2 cents.I would have some real concern with the water level, 3 ft down in a pond this size is a huge percentage of water loss. If my math is correct and you have a water source at even 10 gpm you could replace 3 ft of water in 17.36 days. Fish load > Is 900 trout per acre a lot for your situation, I see stocking rates to 400 common but have not seen 900 to date.Your demand for DO will be great at this level when you ice over thus the thinking that a full pond level would increase your chance for winter survival. Not knowing what pump you have or which pore size on the FlexAir (several available)you have all I can suggest is to aerate at 1-2 PSI max this winter and perhaps with an on and off mode as with the success with BZ (if it works go with it)I would get the lines larger for the winter operation, 1/2 - 5/8 in the water is OK but 1 inch ID on the above ground portion would be better. Here is what works for us, look into a Koender/ Superior type freeze control unit as they can be adapted into any type of pump (I have some pics on our installation page)These units open at 12-14 psi backpressure and do a great job.Will your poly line handle the extreme cold, not sure as I only have experience to approx 20-30 F below zero and use Lowes silverline with no problem, Contact the manufactuer as they may have those specs.

Good point, Ted. I was thinking about this and forgot to add the likelihood of brittleness with extreme cold to the pressure from ice expansion in my mental equation.

Maximum, I think Bill has re-posted about all I know on this topic. Please do keep us posted on your progress.

For what it is worth, I have a small pond (1/4 Acre about 12 - 14 feet deep when full) in Northeast Minnesota about 30 miles southwest of Duluth. I live a fair distance from my pond so I can't get there immediately after a snow. Prior to this year, I did not have power available so I tried to go up on weekends and clear snow. I thought based on Woods experience, if I could keep the snow off the ice, the trout would be fine. Both winters my trout looked great (using an aquaview camera throught the ice)until sometime around late February when I had what appeared to be a complete fish kill after a heavy snow storm that I didn't get cleared for 2 - 3 weeks.

This year I don't have fish in the pond going into the winter. I lost them during a record period of high temps this summer. There might be one or two strays, but next year I'm going to restock again and use an aerator on one end of the pond and see if I can get fish through a winter. So far between winter fish kills and record summer heat fish kills I'm 0 for 3 with trout.

BZ - I'm curious what kind of fish you are raising. Maybe I just need to try something different since trout are a little more sensitive than some other options.

birddog reinforces the improtance to removing DEEP snow from a small pond to maintain high levels of DO during ice cover. Early removal of snow after a decent snow fall is no doubt more important, if trout are in the pond since rely on a higher DO than most other fish.

As Ted Lea often suggests, an alternative to removing snow can be operation of the aerator long enough to clear a decent sized open water area over the diffuser. NOTE - Beware of producing hypothermia upon the fish due to extended or excessive aeration during ice cover. Once open water is produced then allow the water to refreeze as CLEAR ice which will allow lots of sunlight into the depths for plant photosynthesis which will cause an increase in DO. The critical segment of this MELT-REFREEZE method is how big of an open water area has to be produced to allow adequate DO production due to sunlight penetration and photosynthesis. This will be dependent on several things such as species of fish, ratio of open water area to size of pond, clarity of water, number or amount of sunny days, and amount of phytoplankton in the water column. Numerous IFs or variables are involved here.

birddog, I'm raising HBG, bass, and crappie. Ted brings up a good point earlier about high fish density in small ponds. My pond is 1/2 acre and my original stocking was 1000 HBG, 100 crappie, and six bass. All these fish have reproduced so I'm sure I have several thousand fish. I have never lost a one to winter kill that I know if (I assume they would float). I would consider my pond to be stocked very heavy and yet no problems. Is this because of aeration? I may never know until I shut it off which I'm not planning on doing. I do exactly what Bill is talking about above. I run the aerator just enough to keep an opening/thin spot in the ice. I determined the run time by trial and error along with a few water temp measurements during the coldest weather. I also try to plow as much as I can.

BZ- Thanks for the info - Do you have any trouble with your airlines freezing? Can you describe how you have your system setup, for example how far from your pond is your aerator, what diameter hose do you use. Also do you have any water flowing through your pond or is it an excavated pond.

My pond is a little deeper but only 1/4 acre in surface area. Although this fall my pond is now down about 4ft (still about 8 feet deep) due to the very dry summer and fall.

during the winter, do you run your aerator on a timer daily or are you close enough that you can just turn it on and off as needed. My pond is remote from where I live so I need to come up with something I can do from a timer. How big of an area does your areator open up?

Thanks again for the info.

My pump is in an ventilated enclosure about 20 feet from my pond. I run 1/2 inch irrigation tubing out the bottom of the enclosure and into the ground. I buried this pipe about 1.5 feet down. When I buried it I was very careful to keep it sloping gradually toward the pond and then along the pond bottom with weights. It enters the pond under water about 1.5 feet below the surface. I carefull sloped it because if you get low spots in the pipe it could collect condensation from the pump which would then freeze. The pipe is obviously not deep enough to avoid freezing. I have never had a problem with freezing. I have no flowing water in my pond, it is simply excavated in low ground. I run the aerator on a timer, 4 hours starting at midnight and 4 hours starting at noon. I would caution to remember that my pond is basically figure 8 shaped. I run aerators in both sections in the summer but in the winter only in one section. I truly fear that if I ran them in both sections, or if my pond was just one round pond rather than two sections I think I might have to run the aerator much less to keep the water from super cooling. I would be very careful. I am pumping 5 CFM and when it gets below 0 deg. F. it is not enough to keep an open hole with my running schedule. But it does keep a rather large thin spot. I installed my aerator the year before I stocked fish and spent one winter just experimenting with the aerator schedule to determine the amount of run time. That would be the best approach but if you already have fish I don't know what I'd do. You could kill them all if you run it too much.

Spring Update on my first winter aeration experiment, hope everyone had a great winter.

I ended up running my aerator all winter in the shallow end of my pond and kept the ice open for about 2to 3 feet circle for most of the winter. Our temps here got down to -40 C and lower for a few weeks and the ice formed over the air station in the shallow end. At this point I thought maybe the pond froze to the bottom in the shallow end. I switched to the air station in the deep end and ran the aerator approx. 12 hours per day for a few weeks till the shallow end would open up again. Just this last week the ice started breaking up from the edge and I seen minnows coming to the edge of the shore in a panic then the clear water turned muddy and I seen the first trout. So it seems that the trout survived the winter , how many I am not sure . I started the winter with approx 300 - 1 to 1 1/2 pounders.I tried feeding them last night and only a few came to eat. But they are jumping and getting more active very day . I was scared that maybe I ran the aerator too much this winter and superchilled the water and maybe harmed the fish but time will tell .

Next problem is now the influx of Blue Herons arriving with spring to feast on trout,I guess its time to run them off.

Maximum

If it makes you feel any better trout are not as easily stressed by cold water as the warmer water fish. I'll bet you'll be fine.

As far as the herons I wouldn't advertise your intentions unless Canada treats them differently then we do in the states. And yes, I know others do the same on here but it's not wise. Just some friendly advice and keep us posted.

Maximum,

I would suggest that you should know that Herons are a protected species in Canada.

If you read on Heron feeding habits, you will see that about 60% of their diet is frogs and insects. Being opportunistic, they will once and a while pick one of your trout, as will king fishers, otters and minks. Mostly they will target minnows and shore dwelling creatures.
Once water warms up a bit, you should not see any trout in shallow water as this is going to be too warm for them. Plus trout are very afraid of these birds.
Loosing trout to herons is like loosing deer to coyotes, not fun but a fact of life.
Consider that loosing a few trouts to the herons is like paying interest on loan money... it cant be avoided... and killing all herons will not work as more will come!!
Learn to love the creatures, you'll see how regular and steady they are, they will always come at the same hours, do a walk, pick a few frogs then move on...
If you want to prevent them from coming, just install a fishing line about 3 feet off the ground that goes around the pond, it won't like to get tangled in it in case it needs to fly away. It will avoid it, and may abandon your pond. The fishing line, if well tighten wont be seen and will keep the pest away! It works for geese too!

For the aeration, I have clients who aerate their pond all winter and with the snow cover we get here, do not have super cooling problems. They mostly loose trout due to lack of aeration than too much aeration. Keep posting, its fun to hear about our frozen north that is finally thawing!

Maximum I fixed your post. You never know who might be reading . Its your pond so deal with things the way you want to and don't feel compelled to do things the way others say you should.

Hey ewest thanks for help ,I understand some peoples thoughts on the Herons and I think the trout now are too big for the Herons .I will let them feast on the frogs and minnows . I put a horse trough full of shiners in my pond each spring for food for the trout. Get them locally at this time of the year out of the ditchs leading from a lake close by .

The worst problem we have here is the Commorants and I have seen first hand how much damage they can do to a trout pond . Once they know there are fish in the pond they will not leave to they have eaten every one, and of course these suckers are also a protected species. I tried a floating gator last year to no effect didn't scare them a bit . But they do seem a little shy when I go visit my pond with my trusty sidekick Browning. Take care all. Thanks for all the advice and help. This is great place for info.