In one of my fishkeeping magazines they had a article on this. I was planning on using 2 eheim pro 3's but this seems to be pretty good and I think 2 of these are about the same price as 2 eheims. Anyone heard anything about it? Here's a link to a site selling it (sorry it dosent have much info the official site is down at the moment and this is the best I could find.) Fluval FX5