Backwashing sand filter issue??

[Chillin-the-Most]

When backwashing my sand filter the flow/ output is very low and I have some slight flow returning to the ag pool as well. When filtering pressure and flow are good but both backwashing and rinsing have low flow and some flow in the return to the pool. Any thought would be appreciated!!

 

[YippeeSkippy]

My first guess would be a damaged gasket at the multiport valve.

Can you please make a signature line up giving us details about your pool, its surface type, and your equipment to include your test kit. Thanks.. it helps us answer faster without having to ask redundant questions.

Maddie