skimmer making a wopping sound all in a sudden

[KevinK]

when I do this, than I change the conditions, kind of, as than I have to get water from the tank into the tub,

there is than less turnover of mix water, as it is always the smae water (in the tank, it takes a while before the same water gets in the skimmer again, in a tub, it is kind of out of the skimmer and derectly back in)

and than, I end up with kind of the same now, the general noise of the skimmer + maybe a wop, wop.

I was hoping something in the tend of that somone knows if it is gust to much air for the amound of water getting into the pump (than I need to lock at the water intake,

ore it would be to much water for the amound of air (than I have to lock into the air hoses, and conection from hose to pump housing/intake