Problem with backwashing filter

[jnorris]

Hi, Judy.



Yep, almost couldn't be anything else. The water comes out fairly dirty when your backwash, doesn't it?

Actually, when I backwashed a couple of days ago, the water didn't look dirty. The first time we did all this brown water came out, so I could understand that. But this last time I watched the sight glass and the water was always clear. My pool water has been clear and blue since we started. We don't have trees around it, and we haven't done much swimming. We do have a heater, and have used it a couple of times. My FC reading is a little low (2ppm) for the amount of CYA I have in there (40), so I'm wondering if there could be algae growning that I'm not seeing? Anyway, I'm going to start using chlorine and take the sticks out of the feeder so I don't add any more CYA, bump the FC level up to 3 - 6 ppm, and call the PB to come check the filter.

Thanks for all the great advice!
Judy

[mshumack]

If this is a "new" gunite/plaster pool you may have a problem with plaster dust coating the filter.

I have a DE filter so I don't know if this applies to sand too ... but when I first opened my new pool I had a similar experience where I had to backwash often. The first backwash dumped a lot of dirty water. After that, the next time I'd backwash the water would flow out clear and return the pressure back to normal for only a few days before I needed to backwashed again. After a coupkle of weeks of this disassembled the filter and found the filter grids covered with plaster dust. Teh backwashing was not removing this dust (paste). I was able to wash the palster off the grids with a garden hose. I never had that problem again after that.

[jnorris]

If this is a "new" gunite/plaster pool you may have a problem with plaster dust coating the filter.

It's a vinyl pool. My husband now says the water coming into the pool from the returns and jets has decreased since the pressure has gone up. After we backwashed the other day, we had good pressure and could have the returns, the jets at the steps, the jets in the swim-out, and the deck jets all running with lots of bubbles. Now there is hardly any ripple.

PB is coming out tonight to check.

Judy