Dirty water from filter fills pump basket when draining filter

[jark87]

When I drain my DE filter to clean it, the pump basket fills with dirty water, which I assume is flowing back from the filter. After cleaning the filter and starting the pump, that water them flows into my pool, most notably in the spa since that has the largest return. It makes the spa and pool cloudy, but clears up in a few hours. I’ve had the pool for 14 years, but this just started happening in the past year or 2. I’ve read where you can put the backwash valve in the backwash setting to prevent water from flowing back into the pump basket. Is that accurate? Any other fix? Kind of ironic to clean the filter only to end up with a cloudy pool. I’ve posted some pictures below. Thanks for any help!

Filter basket getting dirty water as filter drains:


My backwash valve:

 

[Texas Splash]

I'm kind of wondering if there's not a bad O-ring in that slide valve letting water out? Let's tag @Jimrahbe for his thoughts.

 

[jark87]

Thanks for the response and that makes sense. It’s probably the 1 o-ring I haven’t replaced. I’ll wait for Jim’s response before digging in on how to replace it.

 

[Jimrahbe]

87,

If you just open the air valve, or take the pump lid off, you break the vacuum and I'd expect the filter to drain back into the pump and pool...

But.. if the backwash valve is in backwash position I would not expect that to happen..

That said... I have never used a two position backwash valve like yours, so I have no practical experience with the problem.

Thanks,

Jim R.

 

[jark87]

I’ll try putting the valve in backwash position the next time I clean the filter. Thanks for the quick responses!