I'm wondering if anyone has insulated their sump with foam. If so, how much of a difference did it make in how much your heater ran? I'm also thinking covering my sump with glass lids. pro's: - preserve heat; efficiency; same electricity - reduce evaporation Cons: - reduced light to my chaeto - needing to clean off the lids - reduced air exchange Although, from what I've read I shouldn't need to worry about air exchange if I run my skimmer and don't cover the display tank. I have a canopy on the display with a fan of needed. What your experiences and thoughts? Mostly, I'm thinking of my 180 build and trying to save on electricity and am concerned about the amount of evaporation and therefore humidity in my home. .