I have 3 tanks; 30 gallon(fluval 3+ filter), 18 gallon (fluval 2+ filter) and a 3.6 gallon (fluval 1+ filter). I got a fluval 205 yesterday and will be setting it up at christmas so then i can move the filters down a tank (3+ going to 18 gal, 2+ going to 3.6). So i guess thats pretty good filtration as all the filters are well under their maximum limit! YAY!!