As I am much further south of you, I don't have the long winters like you. But I have a small aquarium pump and my airstones are kept about 4-6 inches below the pond's water level. One stone is in front of the skimmer opening and the other along the edge of the pond. I do it to keep a hole open in the ice so gases can escape the pond when it freezes over which it did quite often last winter. As for circulation, I can't advise on that because I keep my pump, skimmer and waterfall going all winter, but I know being much colder, more people north of me aren't able to do that safely and shut things down.

wiz, the source that told you about the circulation thing is an abject moron. Typical though.

A frozen over pond will indeed stratify. 32F just under the ice, maybe 39F at the bottom.

But any movement at all, from air or pump, will produce a current which stops stratification almost instantly. Even ice is required for a pond to stratify as wind alone is enough to create currents.

Your question #2 is your answer...how indeed. And that's how you have to approach things you read...question everything. I'd say 90% of what is written about ponds is completely wrong. It's because people just repeat what they hear and maybe combine it with something else they heard, or they add what "their gut tells them". People are far too lazy and dumb to actually learn things. It's easier to just type stuff that sounds good. Combine that with the rest of us willing to accept crap as fact.

Keeping a pond open in winter is a Catch-22. Gas exchange is an issue in some ponds, but so are the low water temperatures created when keeping an opening. Kind of hard to tell ahead of time which is a bigger risk to your specific pond and your specific winter.

Rapidwiz,
Before I would even think of giving any advise I would like to know a little more about your pond. You say you have a 4.5pond. Can you please explain to me what you mean by this? Second what kind of fish do have in this pond? Third what climate zone is the pond located in? Also do you shut the pond down for the winter or do you keep it running?
Mike

Thanks Guys.

Sorry I meant to say my pond is 4.5' Deep and I currently have the air or aerator tube right at the bottom of the pond. It makes sense it is churning up the water and circulating the cold to the bottom of the pond. It's a fairly new pond that I built in 2010 and I have had it running since thru our winters, which typically is not too cold. I am in Zone 5. We have a couple of short cold snaps where it drops to about 15 degrees F for a week at a time, but would guess it typically stays around the 25-30 thru winter.

The pond is fairly small, 8' x 10' x 4.5'. I have the pump and filter going thru winter.

Thanks a lot for all the replies.

I live on Vancouver Island and keep my pond(6x10x42"d)running all winter...waterfall 1ft high,it still froze over last year. It looks pretty mild this year so far...I'm liking that! I too have heard that you set the aerator 1ft off the bottom. I just built my pond 1.5yrs ago and LOVE having it!

Rapid wiz I am zone 5 also
I leave my pump running all year long no issues with my pump
or water fall. I have a 4 valve aerator with 4 round stones
2 in the bottom of my bio falls 2 in my pond about a foot off
the bottom no problems run all year long.
My pond is17x10x4 at the deep end. Just my 2cs

My spouse converted a 450 gallon hot tub into a tank. She removes the filter but leaves the pump on in the winter. She has a venturi at the intake to the filter pump which sucks air from outside and releases it in the tank. Last night temperatures got to 7F and ice was about a centimeter thick but the there was a hole in the ice where the air was bubbling up.

Albert,
I hope you are not using the high pressure pump that came with the hot tub for the venturi.
Mike

Albert,
I hope you are not using the high pressure pump that came with the hot tub for the venturi.
Mike

No. Don't know where she got either.

Has anyone made the skippy aerator