If you are planning on changing the water circulation pattern for the winter...

[MitchM]

...do it while the water temperature is warm, before your pond's biofilm layer starts to slow down.

The biofilm layer in your pond is your pond's most important filter. It is responsible for reducing harmful ammonia to much less harmfull elements.

A change in water circulation will disturb pockets of debris/detritus that have settled over the summer. When these pockets of debris and detritus are disturbed, that will expose partially decomposed organic matter to oxygenated water where bacterial populations will suddenly increase, consuming oxygen and producing ammonia in the process.
Depleted oxygen levels and increased ammonia levels could stress your fish.

"Warm" water temperature will be relative to your climate. If your pond temperature only drops a minimal amount during the winter, this will not be much of an issue. As your pond water temperature drops below 77f, the conversion process of ammonia to nitrate is gradually reduced, so you want to change any water circulation patterns while you still have the biofilm operating at peak activity level.

.

 

[addy1]

Thanks Mitch, I prefer everything turned off, except the pond breather

 

[MitchM]

Thanks Mitch, I prefer everything turned off, except the pond breather

This year I'm going to be adding a 600gph Laguna submersible pump strapped to a milk carton on the bottom of the pond in an attempt to minimize the ice cover this year.
I know it will disturb pockets of detritus that have built up over the summer, so I'm doing it while I still have relatively good filtering processes in place.

.

 

[Dave 54]

Good sound advice Mitch hoever I have a set of four healthy filters and a bottom drain which during the winter is cleared bi weekly in the form of a 40% water change trickling the replacement water through our dechlorination filter using the ambient temperature of the ponds water to warm the new water as it enters the pond.
Done correctly all I will use is .2c
As such I have a clean pond clean bottom drain and mature filters .

Dave

 

[MitchM]

If you can run filters year round, Dave, that is a different matter.
Water lines here are 8' (2.5 meters) deep. Anything above that can freeze solid.
That changes your approach to a winter setup.

 

[Mucky_Waters]

Water lines here are 8' (2.5 meters) deep. Anything above that can freeze solid.

So do you get 8' of ice on your pond?

 

[MitchM]

No., but at 8' deep, there is no chance of freezing/ground heaving that would damage water lines.

 

[Dave 54]

If you can run filters year round, Dave, that is a different matter.
Water lines here are 8' (2.5 meters) deep. Anything above that can freeze solid.
That changes your approach to a winter setup.

All our pipes the pond its walls everything is insulated Mitch weve been as low as -15c with no problems our ond sits above ground so the frost line doesnt effect it at all plus we have the policarbonate roofing sheets over the pond and filter housing

Dave

 

[MitchM]

You pond sits above the ground, or on the ground, Dave?
Plus your pond has pretty good protection from the wind, which is THE major cause of pond heat loss.

 

[MitchM]

This thread isn't meant to be about frost depths, it's meant to be about cold water, winter water circulation and biofilm effectiveness.
I've seen a few posts lately where people are just now considering separate inside pond setups and i would like to start some discussion about why it is better to start these setups well before pond temperatures start to drop below maximum biofilm activity.

 

[sissy]

The part of my pond that is above ground i insulated with foam core insulation just in case .I did not get to that part last year but I did this year .Part of my honey do list .Trying to find every point that anything can go wrong

 

[MitchM]

sissy, that's great that you insulate your pond walls.
- but I've seen many times where people talk about insulating their pond walls as if insulating actually heats the pond. It does not. All insulating does is slow the transfer of heat from one location to another.
What is really important is how much of a temperature difference is there, and how long does the temperature difference last?

 

[sissy]

My pond is only a couple of feet away from my septic tank and it gets heat from that .The wall above ground is only 2 feet on the sides that I can insulate ,but figure it could not hurt to keep the block from getting colder and allowing the water to get colder .I noticed last winter that the side edges were freezing faster than the center of the pond .I know people here thought i was crazy when I had my basement done thought it was a waste of money to insulate the slab of the basement and insulate the walls ,but to me it was worth it .They even laughed at the 2x6 stud walls and triple pane windows .oh well To spend a little money to save a little money was not my objective ,my objective was to stay cooler or warmer .

 

[CometKeith]

Mitch,I usually remove my biofilter Nov 1st and leave my smaller pump running to the waterfall all winter. So far the last two years this has worked out well. According to your suggestion I should maybe change things sooner but I would hate to take out the biofilter while it is still doing something.

 

[MitchM]

I would suggest adding the winter pond circulation while your summer circulation is still running.
My winter pond circulation would clog up if I ran it during the summer.
I plan on keeping water circulation to a minimum so I can minimize ice cover, but at the same time not provide open water which would contribute to water evaporation and heat loss.