Dirty water flowing back into the pool while vacuming .

[bmbrian]

Hi
I have a 27 ft round radiant pool with a Hayward sand filter. I live in Canada and I am opening the pool for the season. I let the pump run for a day or so and back washed. I am now starting to vacuum the pool but, find that the dirty brown waste water is flowing back into the pool. I tried to backwash a few times and it seems to be getting a touch better? Any thoughts? Bad ring? Sand need to be changed?

thanks

Brian

 

[Texas Splash]

Before we assume there may be a mechanical issue in the filter, best we start with a full set of water test results. Can you provide them for us?