Winter is aproching...do you turn off your skimmer?

In NH zone 5 where nights can go as far as -20 ( luckly not to often)
600-700 gallons pond about 3' deep. 7 ten inches kois and 12+ gold fishes
Water fall powered with a 700 gph pump and now a Savio 85 skimmer
I have a 3000 gph pump in it, should I leave it running or not?
If not, any suggestions on how to keep it from freezing?
I do have a floating de-icer 1250 watt for the rest of the pond.

Giorio, You could save yourself some money by turning both pumps off for the winter and not using the energy devouring 1250 watt de-icer.

In place of the large water pumps and de-icer you could use an aquarium air pump and an air stone to keep a hole open in the ice covering your pond.

The air pump should be kept outside in a plastic container, which has a hole drilled in in to allow for the ¼" air tube from the air stone, to enter and connect to the air pump and an notch for the electrical cord to pass through.

A second ¼" hole for air to enter the container for the benefit of the air pump, can be drilled in one side of the container

If the pump is kept inside where it is warm, the condensation created in the tubing will freeze and block off the air flow.

¼"silicone tubing, though more expensive than the PVC type, is best as it remains pliable when cold and is available with the pump and air-stone from any pet store.

The air stone can be suspended into the water at a depth of about ten inches, where it will send up a curtain of bubbles that will keep the vent hole open in the ponds ice covering.

Or.....

You can use a small GPH water pump suspended about the same depth under the water that will do a similar job of keeping a hole in the ice open by moving the surface of the pond water.

An air pump can use less than one watt of energy, a small water pump can use up to 100 watts, depending on it's GPH rating.
Both however are drastically lower in power consumption than your 700 GPH. or 3000 GPH pumps and more so than the 1250 watt de-icer, even with it's thermostat control.
Oconus.

With so many fishes, do I need to keep any biological filter going ? Or, is everything going dormant during the winter?

Wow, your received excellent advice on overwintering the fish in your pond and turning off the pumps to your waterfall and skimmer.

Turn off your biofilters for the winter too. All will be fine with an air stone and little air pump, cross my heart! The first year I did it I about had a heart attack. The individual who responded to you above is the person who ultimately educated me and I might add that this member has educated thousands by talking everyone through the first year of cold turkey cutting the pumps! Oconus us a good hand holder!

I ditched my de-icer for the safety of my fish. Oconus is far more qualified to discuss possible ramifications of using a de-icer than me but this member converted me over to going "de-icerless" too. So here I am entering my second season of pumplessness, biofilterlessness, and de-icerlessness!

Equilibrium, you are too kind, but thank you for your flattering comments.
Giorio, as Eqilibrium said you fish will be fine and as the slow right down during the winter you need not run the bio-filter.
The bio-filter does not do it's job during cold temperatures anyway.
Oconus.

Oh boy! Pulling the plugs will take some courage...
A couple more questions please:
At what temperature should I disconect the filters and remove the pumps?
The Savio 85 skimmer sits in the ground next to the pond, should I remove all the water from it after blocking the entrance?
....again thanks

Giorio, there is no specific temperature/time to do it, but in my opinion, I would do it while the weather is nice and it does not become a chore.
If you wait until some cold day when you don't really want to be out there, you will wish you had done it sooner :)
Be brave.
Oconus.

My ponds, two with a tiny stream from small to large, about 1200 and 900 gal each, are ready for winter. All the lily pads have been cut off low to the pots and moved to deepest part of pond, about 30". The tender things are in my sink in the gh. I am not feeding the fish, there are about 35 goldfish, from 2" to 10" and one 10" koi. Had to start slow with koi to be sure cranes, etc wouldn't catch them. The water is crystal clear. Actually the water in the largest pond where the fish are has been very good all season. The smaller one, my pollywog/frog pond had quite a bit of string algea, but gone now. Pump shut off. Getting cold here now, 25 degrees outside now. Donna

All you can do now Donna, is sit back and dream of next Spring like the rest of us in the colder zones :)
Oconus.