i dont use filtration at all i do have a skimmer and a bit of fine floss just to pick out the large sh*t and thats only a wafe thin bit but i have had nothing go wrong with my tank for over a year i have never done a water change and all my levels are perfect mind you i only have 1 fish my lion but he has bee dead happy and so have my corals i have even propergated them and added home made live rock that i made myself