One thing that should help a lot is to directly insulate the tanks and valves using R-4 or R-8 foil bubble duct wrap over the tanks and pipes. If you want to stick pipe heaters between the insulation and tank, that will really boost the effectiveness and then you will only need to turn them on sparingly, you could probably get away with only turning them on for an hour or so a day. I like this stuff:
https://www.ecofoil.com/R-8-HVAC-Duct-Wrap-Insulation
Get some foil tape to go with it.
I used it to wrap the ducts in my house and a use pieces of it to cover some of the bunk windows in the cold and hot weather to add privacy and comfort.
