i plan to build one of these pretty soon. there is a modified version(
http://www.rl180reef.com/180/pages/s...s/stockman.htm ) that is more compact. since my overflow is HOB i dont have as much space to work in. this one appears to be the same principle as well. im basically gonna cut a filter sock to fit inside the air space that is created under the PVC cap. it would be easy to remove and clean as well.