Hi all thanks for taking the time to read my thread. I've been struggling all summer with my pool. I noticed that the filtering wasn't working as well even last year, so on a tip from a friend I changed the sand a month ago. We put in the correct sand and quantity per the manual (#20 sand and 200lbs) and carefully inspected the laterals, noticing no cracks/breaks. we've been seeing sand in the pool vac and the backwashing is clear despite running the filter 24/7. I added DE thinking the sand was too clean, but it would shoot right out of the pool returns and eventually pile up on the bottom of the pool. Today I reinspected the laterals and do not see any problems, leading me next to inspect the multiport valve. There are no cracks in the multiport that I can see. We replaced the spider gasket a few years ago based on tips on this forum. My system is very ancient, but it doesn't leak. Hopefully I can get a few more years out of her! Questions 1) someone in another thread said sand in the pool probably meant sand in the laterals. I did see some sand in the laterals, but the open ends of the laterals would of course have sand seep into them. Are they supposed to have some covering? 2) What am I looking for to determine if my multiport is functioning? I noticed sort of a gap in the head, but there are intentional holes through the unit. I'd rather not replaced it until I know with certainty that it is the problem. Please help!