Sand Filter not working??

[alan70062]

This has me baffled...My PH was a little high so I just added 8 oz of PH plus powder to my skimmer. About 2 seconds after the PH plus went in dark green water shot out the two return jets for about 5 seconds. Another issue I noticed that I didn't notice until last year is after I vacuum I have to immediately backwash and rinse. If I take the vacuum hose out of the skimmer without stopping and back washing green water will shoot out of the return jets. My pool is 8 yrs old, above ground, 12,000 gallons, sand filter (300lbs), sand changed 1 year ago, 1 1/2hp pump.

The water has been cloudy but my chemicals are ok. I just had my water tested a few days ago and everything was ok. I check chlorine and PH daily. No trees around and I back washed 5 days ago. When I back wash I never see the type of green water that just came out the jets. The water starts out clear when back washing, turns cloudy then clear.

Does any of this make sense? Why would green water shoot out of the jets when I put in the PH plus? Is my sand filter the problem? HELP! lol

Alan

 

[JasonLion]

There are a couple of things that could turn the water green when you add PH Plus. The most likely one is copper in the water. Copper can form tiny green crystals when the PH goes up sharply that tint the water green. Then as the water mixes with the rest of the pool water and the PH comes down it can dissolve again. But that would not explain the water turning green after vacuuming.

 

[Bama Rambler]

It sounds like it could be the sand filter but first post a set of test results. Telling us the chems are fine really doean't help us figure out what's going on. Oh yeah, why did you add pH up if your pH was high??

pH
FC
CC
TA
CH
CYA

 

[JohnT]

I'm betting the filter/multiport as well. What filter do you have? I had a very similar problem last year. Just a little increase in filter pressure and the crud went straight through.

 

[duraleigh]

Alan,

I believe you may have (or have had) inadequate chlorine in your pool. Post those numbers and give us a little history as to how you have been maintaining FC.

 

[alan70062]

My bad...I added PH minus. I will post my readings today, I am going to a couple pool stores to get the water tested. BTW, my water was perfectly clear till I added "Metal Free" per instructions from the pool store. Two days later my water was green and then cloudy after I shocked. I use the 3" tabs in an in-line chlorinator. I had my chlorine level off the chart after my pool turned green, my indicator (5 drops) was orange instead of yellow. I kept it like that for several days then the water was just cloudy. I let the ch level come back down to a 4 and continued to shock once a week

 

[Bama Rambler]

The first thing you need to do is order a good test kit. If you're letting the pool store tell you what you need that's your biggest problem. Get a good test kit, run your own tests, read Pool School, post your results here and we'll get you on the road to happiness. Since we don't know what your CYA number is (and the pool store is notorious for getting that wrong) and don't really know what your FC is we can't rule out an algae outbreak.

The money you spend on a good test kit will more than pay for itself in savings from buying all the chemicals that the pool store would have you buy.