Sand filter is not working properly.

[justlane4]

I have been having an algae problem lately but have been given the information to control it however I run the filter all night when I wake up and go to vacuum it and hit the bad spots where it gathers, most if not all of it is blown right back into the pool without being filtered. I know its not channeled because i cleaned the entire thing out yesterday and still am getting the same results today. Does anyone know why it is not filtering the dead algae out?

[justlane4]

61 views and not a single reply. Not even a guess? Anyone?

[AnnaK]

Could be we just don't understand your terminology. What do you mean with "cleaned the entire thing out"? Did you replace all the sand? Or did you backwash? If you backwashed, did you complete the process with a 30 second rinse cycle? The rinse cycle packs the sand back down and prevents it from blowing back through the return.

Is your multiport valve set to filter? Or do you have it on recirculate while vacuuming?

Does the gasket on the multiport valve need replacing?

Is the handle of the multiport firmly seated in the appropriate slot?

Filtering dead algae can take quite a few days. Have you ever tried skimmer socks? I like them for catching small debris before it gets in the filter.

[aylad]

To add to Anna's questions, is your filter pressure rising while the filter is running? Do you have sand blowing back into the pool when you're not vaccuming? Have you tried testing your filter by putting a cupful of DE in the skimmer and watching to see if it blows out of the returns?