I have another thread under ALGAE PREVENTION as I had an ammonia issue almost 3 weeks ago and although my pool has been crystal clear for almost 2 weeks, I cannot seem to pass OCLT. Everything has been removed from pool. Then today I notice the plume. Maybe this has been effecting my OCLT not passing? So when I have to backwash and go thru the filter settings I'm not by the return when I switch back to filter. But earlier I noticed that when I turned it back on filter I could see a plume entering the pool thru the return for about 30 seconds, then it was clear. When I backwash - I turn off the pump, switch the multiport to backwash, turn pump back on low and watch the clear tube for it to run clear (generally takes a couple minutes). Then I turn off pump, switch multiport to rinse, turn pump back on low and repeat watching for the clear tube to run clear (generally takes a minute or so) . Then I turn off pump, switch multiport back to filter, turn pump back on high. When I noticed the plume I turned off the pump and got a black sock and held it over the return but the plume went right thru the sock and the sock didn't catch anything. However, even if something is reentering the pool, wouldn't it be dead by now from being at shock level for weeks? UGH. No idea what to check on the filter. Thoughts??? Thanks as always!!!