We have a Baquapure sand filter and just replaced the entire lid/multiport valve assembly (with a new spider gasket) and changed the sand. Now when I backwash or vacuum the pool, water is coming out the waste adapter plus coming back into the pool. The water only shoots out of the waste adapter half as far as it used to. The algae I'm trying to sweep from the pool is coming right back in. Does anyone have any suggestions? We're not sure if it's something with the spider gasket or possibly one of the laterals. Any help would be greatly appreciated! It's in the 90's, and I really want to swim!