I used a Rio 3100. Lifereef uses that venturi on their smaller skimmers. I think they use a Little giant 2mdqx-sc, Rio 3100 or a Mag 950.
Here's a DIY link to a powerhead modification you might want to try first before you buy a venturi. It's really easy to do...
http://saltaquarium.about.com/librar...y/aa091099.htm
I want $15 for mine if you want it.
Duaine