I came across a thread while browsing in the Arowana forum. The guy had a DIY Chinese protein skimmer in his freshwater tank made from a upside down powerhead and a water bottle. Does anyone have any info on these? It sounds really interesting.
http://www.monsterfishkeepers.com/forums/showthread.php?t=107135&highlight=chinese+protein+skimmer
http://www.monsterfishkeepers.com/forums/showthread.php?t=107135&highlight=chinese+protein+skimmer