Green pool with clogged sand filter after 2 weeks out of town

[CarlD]

OK. You are going to need to double that amount and get your FC to 25ppm, and keep it there, now that I know that CYA > 100. Don't worry about TA or CH, but get your pH up over 7, first.

[jtran69]

Is 5 cups of borax every night til pH=>7?

[FormerBromineUser]

If you have time, you can slowly add the borax to skimmer, wait around 2 hours, and then retest PH. Add more borax as needed. You need to get that pH above 7 as soon as you can.

[jtran69]

Thursday night I added 2 gallons of bleach and 1 box of borax; PH was not quite 7.0 but more likely 6.9.
Then I added 4 more cups of borax.

Friday 11am, PH=7.2, FC=10.5.
Then I added 3 cups of borax and went to work.
Water is looking better now but seeing some black/gray dirt on the bottom -- another round of vac should remove them.

Friday night plan, please advise.

[FormerBromineUser]

Get your FC up to 25 ppm tonight. Retest 1 hour later to make sure you hit that target. If not, add more bleach. If you have time over the weekend, maintain FC at 25 by testing and adding bleach at least 3 times per day. Some people only recommend 3x/day but I think a 4th would only help if you have time. And no more Di-Chlor panicking!

[jtran69]

At 8pm, pH=7.6. I added 2 gallons of bleach.
At 9:30pm, FC=18. I added 1 gallon of bleach.
At 11:30pm, FC=25. Yes yes yes!

[SunnyOptimism]

You need an accurate CYA measurement in order to know where you are at so you can target your FC properly. Please do a dilution test - mix 1 part pool water with 1 part bottled or distilled water and then redo your CYA test as normal. Take the results of that test and multiply by 2 to get a correct CYA value.

[jtran69]

5:30pm, FC=15, pH=7.5. I added 1 gallon of bleach.
I have about 10 ml of R0013 left for one cya mea and will take it when FC is back to 25.