DE leak

[TML4749]

A LOT of DE is leaking into my pool. It seems to be coming in through the returns. My pool is 16,000 gallons with a raised spa. My filter is a Pentair 60 FNS Plus. I’ve replaced all of the grids, the manifold with the air bleeder, the standpipe o-ring, the o-ring around the filter at the clamp, the spider gasket on the multi-port valve. The multi-port valve was replaced about 3 years ago, but I took it apart anyway to make sure it has no cracks or broken parts. I also replaced the check valve between the spa and pump. Only because I read a small blurb online that suggested that might be the problem.

When I clean the filter I put in 15 scoops of DE per the instructions on the box using the scoop meant for measuring DE. I make sure the grids and manifold are lined up and screwed down tightly. I make sure the manifold it seated correctly on the standpipe.

Also wanted to mention that the pool was replastered in May of this year. It sat empty for about 4 weeks before the replaster was finished and it was refilled.

All suggestions are welcome. I am desperate for a solution.

Thank you

[CGPoolman]

Hi TML,

How many pounds of DE are you putting in the filter with 15 scoops? Sounds like a lot of powder. I think for the 60 you only need 6 pounds, make sure you aren't adding any more than that.

Once you verify you have the right amount of DE in the filter, the most common cause of DE blowing back into the pool is a bad multiport gasket. With the system OFF, unscrew the lid of your filter valve and check the "wagon wheel" shaped basket in the bottom of the valve. It could be worn out and need replacing.

If that doesn't work, check the filter element itself for any cracks in the manifold or tears/holes in the grids.

-CG