I have a 55 gal drum converted to a sand and gravel filter for my 2400 gal pond much like this one http://www.koiphen.com/forums/showthrea ... filter-DIY I know it's a long read but it gives very good instructions.This filter works excellent. I can build one for free except for the sand. I was thiking of building one of these for my pool and use regular pool filter sand. and not have to buy intex filters anymore. Has anyone else done this?