This was very cool. It makes me really want to think of other DIY sump idea. I'd like to put a DiY sump under my 35hex. There isn't a whole lot of room so I don't know.
I've been considering all different types of filters. I see the very sleek looking internal canister filters as well as the external ones, the typical ugly HOB, then sump with overflow box. Pluses/minuses of each? Would you just stick with the HOBs if you were me?
I would just go with a canister for your tank design in my opinion a SUN SUN canister would be the best option and they are very good deal on ebay where lots of people here have bought them and gave they very good reviews. They are around 50.00 shipped.