Hi everyone, My name is Cam, I'm a first time pool owner. I've been lurking through the forums for the last couple of days trying to find answers for my problem. I've found a few threads that eluded to my answer, but I want to make sure I'm certain on what is going on. I have a 40k vinyl ig. I'm running a centurion model pump (all important information weathered off), Triton II sand filter with a 1.5'' SM 10-3 multiport valve. The previous owners didn't shut the pool down correctly during the winter and froze some above ground piping. I've replaced a lot of the piping. I've also replaced the sand in the sand filter and the multiport valve. I have a few questions. Based on some of my research I'll offer a few prophylactic answers. I've ran the pump on recirculate and the pressure on the gauge drops to 0 -- same as when I shut the system down. The pressure out of the return jets seems normal (to a newbie), however when the pressure rises to 30psi the skimmers stop pulling in water and the return jets pressure drops significantly (to what seems to be a dribble). I backwash the filter every couple of hours and the pressure drops back down to 10psi. It slowly creeps up to 30psi. There is a significant amount of sludgy looking stuff that I vacuum up.
Now for my questions:
1. is the pressure due the sand clogging up because the filter is working and the aglae sludge is gunking the sand or did I harm the laterals when refilled the sand filter with fresh sand.
When I replaced the sand I filled the filter up half way with water before adding the sand.
2. I wasn't sure how much sand to put in the filter. I took the advice of "pool expert" I think the guy was a moron. and added 350lbs of sand but I think my model needs 450 -- based on a torn up label on the side of the filter. will not having enough sand cause a significant issue?
Thanks in advanced for the help.