Was wondering if this makes sense at all, or if all I'll do is heat my sump? It's one of the overflow boxes that goes all the way to the bottom, but the bulkhead is near the top (so the box will always be near full). Just seems like a good spot to stash the heater out of harm's (fish) way; my w/d is small so heater in there is a no-go. Also I'm planning to add a 2nd filter, likely a canister...would running it in my overflow work? The tank is eurobraced and the other alternative is having the intake/exhaust pipes running down a good 6" from the side of the tank, which will look pretty tacky. I figure that will do nothing much for mech filtration and crap near the bottom, but I can just vac that...and since I'm planning to do sand at least I won't end up with sand in my filter.