My buddy has like 4 or 5 whisper 30-60's on tha back of his 125. The water is clear and the fish are happy but when he cleans his filters he cleans like 5 of them instead of one. He might as well of gotten a canister or sump. Probally cost about the same.
Although, I think they make big h.o.b.'s for big tanks. Anyone else?