possible cheap venturi
 

I have no idea how well this will work but I thought I would pass it along

http://www.leevalley.com/garden/page...180,33226&ap=1

I tried one for a small skimmer. It worked somewhat, but I think it needed a much bigger pump to get the flow needed to be really effective. I was using a Mag 5 on it. It also tended to spit a lot, so a housing of some sort would help to keep things less messy. I ended up buying a Superskimmer instead since it was cheaper and easier than getting a bigger pump and messing around with it.