Most energy efficient fish room

[Fat Homer]

Come to think of it, your biggest problem or expense may be controlling humidity. Air driven filters can speed up evaporation. They don't seem as bad from my experience if I wasn't using airstones.

Dehumidifiers are expensive to run. Extra Ventilation may cause heat to be pulled from the room and wasted.

Maybe throw some cover over each of the tanks, doesnt have to be fancy but may help cut down on the amount of water lost to evaporation?

 

[Pharaoh]

Spray foam insulation, two layers. From there, you'd be surprise how energy efficient fish rooms can be coupled with a central air driven system.