I don't know what combination I found, but holy cow, my SeaClone is skimming now! It hadn't been doing all that much since I've had it for 1 month. I was always trying to find the right adjustment.
Today, I cleaned out the venuri line and adjusted the flow and less than 5 hours the cup was almost full.
When you empty the cup, be sure to rinse the collection area well, but very lightly rinse the intake portion. If you clean the whole thing, you have to wait till the slime builds up again to allow the foam to rise. I just figured this out and it works great, back to skimming almost immediately.