No experience in Weipro skimmers, but generally, bubbles inside skimmer must be so thick that you CANNOT see through it. If you can see your hand on the other side, than most likely, you need to improve on your pump or other adjustments.

Once that is achieved, you water level INSIDE the skimmer should be just high enough such that you do not get "WET" bubbles in your collection cup. All the bad stuff is in the "DRY" bubbles.

Try to keep to these basic skimmer concepts, and you should be able to adjust ANY skimmers!!!