I mean insulate the pond really well. The first time I set up my pond I didn't use any insulation and my electric bill doubled keeping it at 78 room temp was 70 the heater was running prob 90% of the time. And That was with a cover on it. When I redid the pond because of a fryed pump I put 2" of pink foam insulAtion on the bottom and wrapped it in faced R22 insulation. And made a cover out of 1" foam. Now I set my temp to 80 and the heater is off 98% of the time





