I am so glad I found this page! I just bought a house with a pool last year. I'm going through a whole different issue besides this, but am deep in pool school and plan to start SLAMing this pool next week if all goes well. I have a Harris 24" sand filter and back washed it last week. The back wash didn't flow out as fast as I had thought so I started looking more online and that's when I found this page. I plan to do a deep clean tomorrow. I noticed on the multi-port that the labeled valves were connected opposite (return port connected to pump, intake connected to return hose to pool). The filter pulls water in from the skimmer and water flows out of the port at a strong rate. However when I was vacuuming it seemed like the filth from the bottom of the pool would shoot right back in the pool. Looking for help and guidance on this. 
