My pool has been open about a month and for the most part is pretty clear but it's still not crystal. All my chemicals are good and it's not related to that. I've noticed if any air gets in the pump that sand will get into the pool. Also today after i turned pump off to clean skimmer, pump baskets of course it had a little air in the lines when i turned it back on and it kicked a good bit of cloudy water back into the pool for at least 10 seconds it seemed like (I put valve on closed while i cleaned skimmer basket). I have a new top half of the multiport valve and have replaced the spider gasket held down with silicon. Is the only thing left it could be is a broken lateral? It is an old sand filter. Other than when a little air gets in the system it seems to do good. No clouds out of returns if I add chems straight to skimmer.