Metals coating bottom of IG pool

[Ossiecat22]

My liner is just two years old. We used the city hydrant to fill it. Last year, I just thought the edges where the sun hit it were causing fading. This year the white film is all over. After some reading....I realize I've been doing a few things wrong. I always kept my I chlorine high...like way too high (~20ppm). Not a wonder I needed to add PH increaser all the time. I also tend to keep it around 90 degrees....we only get about 3-4 months to use it and like to swim at night. So anyway, I did the Vitamin C test and the stains faded. It took 6 lbs of Sodium Thiosulfate to bring the chlorine down and I used 1000 Vitamin C tablets. The local store sold me Spot Clear to remove iron. I used 4 pounds for a 30,000 gal pool. Less than half an hour later.....my pool is green! And I had the filter running, not on recirculate. Oh, and I vacuumed the bottom too......Now what?

Do I need to change the filter sand?
Do I need a sequester agent?
Steps to balance?





Mary
30,000 IG pool, vinyl liner
18x36 kidney shape (22 at widest)
Sand filter, city water

 

[Ossiecat22]

Can anyone give me some direction?
FC=0
PH=7.2
TA=180
CYA=100
TH=250

Pool is green.

 

[chem geek]

Welcome to TFP!

I'm sorry no one responded earlier. Is the pool clear green or cloudy green? With the CYA high at 100 (and it might be higher), you'll need to do a partial drain/refill to lower it otherwise you won't be able to add chlorine to kill off algae. You can put at least some chlorine in now anyway. How are you getting these test results? Are they from a pool store or your own test kit and if the latter, what kit are you using.

It sounds like you were using Trichlor tabs before, is that correct?

So in summary you'll need to dilute your water to lower the CYA level IF it is truly high (depends on the test kit and who's doing the testing) and you'll need to SLAM your pool (see the Pool School) if your pool has algae (e.g. cloudy green).