"Richard Tanzer" wrote in message
I too used an air pump and grew ice sculptures where the bubbles escaped.
Unfortunately the air intake to the pump would either get plugged with
ice or slip down under the water. I think there were some curious cats
in the neighborhood that played with the air intake.

So this year I went back to leaving the circulation pump on all winter
and added one of those small (25 watt?) heaters to keep a hole open. So
far, despite cold weather, a hole has stayed open in my pond most of the
time. For a few days it iced over. Snow got into the electrical outlet
and tripped the ground fault interrupter; after I reset the circuit the
weather warmed up and now the pond surface is mostly open.

All the fish seem to have survived.


I've been using an aquarium air pump. By placing it under an
upside down flower pot with a night light inside and a rock on
top, it has kept pumping air pretty well. I plugged the hole in
the flower pot to keep moisture from dripping in. So far, this
setup hasn't had a problem with either the pump going bad
or tripping the ground fault.

Rich

Jerry