The sump configuration was my most difficult consideration. I spent hours trieing to figure out the best way to handle the sump without compromising my design goal and the safety of the tanks ecosystem. I finally settled on the 325 Norwesco plastic cistern, insulated and buried right outside the room where the tank sits. I like it. The tank is big enough I can get in it if need be. It offers a lot of room for filter socks, a refugium, ATF, and other thing you would put in or connect to your sump. Check out the pics