Filter Problems

[jkugler76]

Hello. I'm looking to diagnose an issue with my filter. I have a sand filter with a multi-port valve. This is only the second season using this filter. The initial problem started when water was leaking out of the waste port while the valve was on the filter setting. There was a steady stream of water coming out. Normal operating pressure is 10 PSI, but it would dip to 8 or 9 while water was leaking out of the waste port. I opened the valve cover to inspect the spider gasket and everything looked fine. No issue with the spider gasket. The standpipe looked fine as well. I have an identical spare valve purchased the previous year, which has never been used. I swapped it out with the existing valve and same problem occurred. I backwashed the filter a few times. After each backwash, the PSI went back to 10 and the water leak out of the waste port stopped temporarily, only to start leaking again about an hour later. I've been dealing with this for two days now. Today, I left the filter on and went out for a few hours. When I came home, sand was coming back into the pool from the return. PSI is now at 0. I had to shut the filter off to stop sand from entering the pool. Now, I'm at a loss. Could the issue be isolated to one main problem or multiple problems. Any ideas would be greatly appreciated.

[Denniswiseman]

Water leaking out of waste port is the spider gasket. It may look fine but there is something wrong with it
Sand coming into the pool would indicate a broken or split lateral in your sand filter