I tried to go this route but just couldn't justify the pump I would need to come close to what the power heads were producing. I built a closed loop with a Mag 9.5 w/scwd wavemaker but really need at mag 18 to have it be at the level I wanted.I've heard a lot of good things about Koralias, but never used them. Another thing to consider is a closed-loop system with an external pump, which is what I'm planning on doing to replace my powerheads.