I have my system indoors in the basement. Through its de elopement one of the thing I liked was year round controlled environment. The one thing that I did forget however was that concrete sucks heat out of whatever it comes in contact with. I noticed the last few weeks a steady decrease in water temps and deduced that I should have insulated the bottom of the tank from the concrete. I thought I would post this up so any new people researching an indoor system don't make the same mistake I did. The fish really did not enjoy the water level drop so the tank could be lifted enought to slide the insulation board in place. Beside the work involved was tough on my back. Live and learn but learn from others as many of the hard lessons. Happy building!