I have a 7 year old Sta-Rite 240BP sand filter with a 112-148 multiport valve. Last year I noticed a small amount of sand in the bottom of the pool but it was very slight and manageable. Opening the pool this year, I decided to replace the sand and inspect the laterals. The laterals looked great. I thoroughly cleaned all of the parts and replaced the sand with pavestone pool filter sand from Home Depot. I started the pump on backwash and allowed it to run for several minutes, rinsed, backwashed a second time, rinsed again, and finally set the vale to filter. After 24hrs of run time, I noticed sand build up on the stairs and edges of the pool liner. I removed the sand by vacuuming to waste. It’s been another 48hrs and more sand has accumulated. I found that the spider gasket is damaged and needs to be replaced. There is no water leaking but the gasket looks horrible (probably 7 years old). I found a few sites saying that the gasket could cause sand to enter the pool. I asked around at my local pool places and they said there is no way the bad gasket could cause sand to enter the pool. I haven’t replaced the gasket but will in the next few days. Could this be my problem??
Also, Home Depot lists pavestone sand on their website as 50lb bags. I weighed the bags to make sure and found them to be only 40lbs!!
Thanks for the help