I think I know what you are talking about. I have no experience with these types of skimmers. But I did find a link that may help. The documentation is rather poor.

From this link download Wall Mount Surface Skimmer - USA (80PO).pdf

Here is the link

http://www.intexdevelopment.com/proi...gid=2&lid=5473

Not sure, but I would think the suction would pull it down enough to create the skimming effect. Might need some adjustments?

Sorry I can't help more.