Okay so the simple answer is of course to buy a quality Protein skimmer and ditch my so-called DIY skimmer, and that might actually be happening so please don't tell me to buy one. That said here is my issue, a couple months ago when I pulled my "reef tank" back over the brink I needed a skimmer and couldn't afford one so I took a couple lengths of ABS and an old powerhead and made one for the sump. The base is 12 inches of 3" ABS, up to a funneled adapter, into a 6 inch piece of 2" ABS, through a 180 deg wide arc to the collection cup. The power unit is a 300gph powerhead (with a small air pump auxillary) going through the side of the 3" ABS body with 2inches of flexible tubing. The first week it ran well even without the air pump, but then just stopped. I was cleaning the other skimmer on my FOWLR almost daily so I thought maybe it was dirty and took it apart to clean. It was filled all the way to the outlet with foam but no skimmate in the cup. I reassembled it with a piece of 2" ABS that was an inch shorter than the original but I am having the same issue. The foam comes right up to the end of the pipe but never falls in the cup. Should I cut it shorter?