Walter Wu asked which foam filter fit the Quickfilter. I use the Hagen Fluval 3 Foam Filter Sleeve. The Quickfilter is the only filtration that I use in the 180 gallon. That Fish Place used to sell them; however, they were prohibited from shipping into Canada at that time. Hagen may have been guarding their market here. -- Dave Whittaker ac554 at FreeNet_Carleton.ca