I'd say the CPR overflow would be fine (CS90), use an Ehiem 1048 or a Mag 2 or 3. AquaTek also had a used 30Gal Sump for $30 the other day. I'd go to one of the local stores (AquaTek) and ask for help. The online guys can't help you when there are issues. Plus its a pain to take stuff back online :-D