Ok I have strong suction and and my pressure gage sits at 15 psi. After approximately 10 minutes or so the pressure climbs to 22 psi at the multi-valve pressure gage for the filter, and the return jet pressure drops to a very faint return to where the water isn’t even moving. I can’t seem to find the issue. My pump stays primed even at 22 psi with no bubbles in the pump filter. However if I change the multivalve to recirculate and it sits at 13 psi, I monitored it for approximately 1.5 hours and the psi doesn’t move. I’ve replaced the filter sand, the fitting from pump to multivalve, the multivalve itself, and the valve is new. I’ve checked for leaks on the pipes that are above ground And it’s not leaking water anywhere. It’s a Hayward S200 filter and a Hayward super 1 hp pump. Any help would be gratefully appreciated.