I am trying to figure out what to do. I have a pond that is only 2.5 foot deep (came with the house) 750 gallons, houses 2 koi and 4 goldfish. . I finally got everything sorted with the filtration to keep with with the fish waste and keep the pond clear. I did not expect the weather to change this quickly and I am trying to figure out what to do. Right now, due to the monday holiday, everything is delayed until tuesday for arrival. Anything i order may be too late. A 1000 watt heater will take over a day to heat the water 10 degrees... that's about as much as I am going to get on a 12v 20 amp circuit . I cannot find any pool/pond cover locally to keep in the temp. Is there a DIY solution I am missing?? I'm thinking water heater elements in some kind of inline container... only id have to get 240 out there.
I am worried that the temperature swing could kill them, mainly due to that happening to one of the fish last year shortly after i moved in. Any help would be appreciated.