Hi everybody. My pool water has been crystal clear until today. Here's the situation. I bought a robot cleaner last year which didn't work when I got it and now it's quit again. I'll post that in another forum. None the less, the pool has been sitting with several small piles of dirt in the bottom which I periodically brush up to get it circulating around. As I said the water has been crystal, the best ever. However, tomorrow afternoon my wife has a freshman girls youth group coming to swim. So I got out the old PoolVac and got it to going. Before putting it in I backwashed the filter which I hadn't done in probably 3 or 4 weeks. For some strange reason when the Pool Vac is connected it sucks in air. I haven't been able to locate the air leak but its only when I throttle the bottom drain line to get the right dP for the PoolVac, which I can't get the 10" wg it needs due to too much air. That's why I bought the robot. Bummer. Again, that's for another forum. With the air entrained I get lots of air bubbles in the first return. The question is why did my water get hazy and it did it really fast. Was it the backwashing or tiny bubbles increasing PH which I don't see how that could happen that quickly. Could it have been something else? Here's my #s: FC 5.5, CC 0, PH 7.6-7.7, TA 90, CYA 45-50.

Thanks

The haziness is from all of the people swimming. Everyone who swims brings along some dirt and organic debris. It takes the chlorine a little while to break all the organics down and the filter a little time to filter out all the dirt. You should raise your FC level up a little higher than normal and it should clear up in a day or two. Watch to make sure the FC level doesn't drop suddenly. If it does you are starting to get algae and need more chlorine right away. Most likely all you need is just a little more chlorine, and everything will be fine.

Thanks for the reply. One thing to note is that no one had been swimming in it for a week. I'm thinking maybe I didn't rinse good enough after the backwash. I upped the bleach last night to probably a little short of the shock level and it seems to be a little better today. Still not crystal but pretty good.

The numbers you posted wouldn't seem to contribute to the cloudiness. It sounds like you have identified your problem. Did you see any dirt from the returns when you put the valve back in the filter position? How long did you "rinse" before returning to "filter"?

I rinsed about 20 seconds. It looked clear in the sight glass but that's a small sample and may have not been "sufficient".

Yeah, all filters are different but I would suggest at least one minute for the rinse cycle. Mine takes a full two minutes and still spits back a little dirt from time to time. I'd say you have it diagnosed correctly.