Searched the forums & did not see this issue addressed.

Replaced the spider gasket in my multi-port valve 9 months ago. Now when backwashing, the water empties out of the waste line. The valve assembly itself (spring, plate, etc) is in good shape, but the spider gasket seems a bit raggedy.

Before I replaced the spider gasket the 1st time I researched the internet & I seem to remember several recommendations to install a shut off valve on the waste line because spider gasket, reportedly, can be problematic and often leaks.

And, from an engineering perspective (yes I am one of those, an engineer) the whole multi-port design seems pretty dodgey at best anyway. So I was wondering instead of replacing the spider gasket (there is no leaking when with the valve in the filter mode) are there any ramifications to installing instead a shutoff valve on the waste line then turning it off when backwashing? Would this adversely affect the backwash function or other filtering functions?

Thank you.

What type of multiport valve do you have? First check to make sure the part you took off to get to the gasket is put back on correctly, if that is not the case did you use a special glue to hold the spider gasket in place if so then go to your local pool store and get the right glue

Thank you for the response.

Not understanding that backwashing empties the pool, my wife ran the backwash for 10 minutes & so a lot of water went to waste. I saw that the pool level was way down & assumed there was a leak in the valve.

And so I investigated & the valve gasket was in place, a little rough, but still functional. That's when our pool guy told me how the backwashing works. So my bad, as it were.

Thanks for answering.

That's good to know. A bit of advice don't touch the multiport handle while the system is on wait until movement has comepltly stopped. And when backwashing always backwash until it comes out clear multiple times
Until you get nothing when using a de filter. Good luck with your pool and remember to stay away from any pool chemicals with copper in it