Vacuumed Debris is Coming Out the Returns

I just noticed yesterday that some of the debris I vacuum comes out the returns. Why is this happening?

90+% chance you have EITHER a problem inside your filter OR a problem with the multiport valve.

Do you have any advice on what signs to look for to determine where the problem lies?

What type of filter?

Noticed my sand filter shooting some debris through the returns this year. After 9 seasons with the same sand I decided to open up the filter and take a look at it, turns out I was missing some (actually, a LOT...it turns out the laterals were never installed flat, so a little bit of sand was shooting through a few of them....a little bit at a time over 9 seasons adds up).

Changed the sand and filled back to normal level and I no longer get anything shooting through during vacuuming.

Has this happened from the beginning, or is it a new problem? Have you backwashed the filter lately? Do you get sand shooting from the returns when the pump comes on? Do you see sand collecting under the returns in the pool?

I just noticed this problem the other day so I don't think it was all along.

I have a DE filter. I have not added any DE and I have not backwashed yet. The previous owner opened the pool and said he put in DE. This was about 3 weeks ago.

Do you think there is not enough DE in the filter to catch the debris?

You have two threads going that are basically about the same question, so I'm going to close this one to try to keep all responses about the same question in the same thread.

Janet