I disagree fully, but hey I am just running 4500gph and 4 filter socks, 650ish gallons total. They are easy to change and far cheaper than just about many other filter type. Yes you have to replace them and clean them at different points, but like any filter you have to clean it. Just like someone cleans a bead or glass, or sand filter weekly or a canister, I clean my filter socks weekly, and if you dont notice them getting full on a tank then your not making sure everything is running well on your tank and maintaining it properly. Hence the dead fish. Not the filter socks fault. That is the fish keepers fault 100% not maintaining his system.