I have valves for cleaning system open, the booster pump have a valve for main drain or skimmer, I have tried both neither change anything. I have turned the spa valves, nothing. There's a valve that goes from filter to salt cell and heater, I have that set to open to both I believe. I can the pics, the same the heads pop up only in the pool no matter what I do. The return on side wall has very strong flow, the one beside it doesn't have any. Presidential pools built this pool five years ago, so I don't think it's all 10 of those pop ups are bad. Any advice? Thanks in advance.