Refilling my inground pool; want to get my water chemistry right

[nefretrameses]

FC = 0.2 ppm is way low. Add bleach or liquid chlorine to get to 20 - 25 ppm and keep it there consistently until your pool is clear. See the best guess chart. The other measures seem OK for now. Don't use the Power powder it's cal-hypo and will add more calcium that you do not need - no stabilizer in it though.

I think Doc would agree - the first priority is to kill the algae and get the water clear.

Doc suggested an OTO test kit and keeping chlorine in the orange. It's cheap to test this way, since you should be testing and adding chlorine several times a day during the fight - even (or especially) in the rain. Of course you can use your Taylor kit. Use the 10 ml sample (0.5 ppm per drop). Also, you only need one scoop of the powder for either the 10 or 25 ml sample.

Wait for Doc before draining. If you are refilling from a well, you will have iron in the water. It may be necessary to know how much. Metals and high chlorine usually = stains. You may already have a filter on your well for this if you are using it domestically.

If the algae is not more noticeable on the part of the pool that is most in the shade, meaning side walls, it's probably green algae (shock level in Best Guess). If it is on the "shady walls" it may be mustard/yellow algae (+shock+ in BG). But you're not going to kill anything at 0.2 or even 10 ppm.

[Cracker Red]

Learned a few things over the past day.

Always test your water before adding

Rained nearly 9" in 30 mins yesterday. Had to drain the pool down....then left the thing draining on accident and drained out quite a bit of water. What I'm left with is hopefully an improvement.

CYA 90
FC 16 ppm

Water looks great!

[PoolDoc]

Sounds good!

[nefretrameses]

Woo Hoo! Congratulations! Test before adding and, in general, "sneak up" on the level you want. Add half of what you think you need and retest, repeat. Shock levels of chlorine is probably the only exception.

[Cracker Red]

Just wanted to check in and say thank you!

Pool has never been better.

FC is now 8
CYA is 85

No algae, water is crystal clear.

I do have a question while I'm thinking about it..... approx how much chlorine (10%) will I need to add to raise my FC by 5? Given the pool is 17000 gallons. Just wondering if there is an approx amount to start with so I don't spike it high out of the safe to swim zone.

Thanks again!!!

[Watermom]

For future reference, in a 17K pool, each quart of 10% bleach will add about 1.5ppm of chlorine.

[nefretrameses]

Cool, enjoy it. The pool calculator will also help out http://www.poolcalculator.com/

[Watermom]

The pool calculator is not our favorite one to recommend as it encourages people to add single large doses of things to solve problems. We prefer the test, add, retest, add more if necessary approach.

[nefretrameses]

Yes, I did discuss that approach with Red above - "sneak up" on the level you want. The calculator will certainly give a "total dose" which can then be applied in several doses as you describe.

[PoolDoc]

If you do it that way (divided doses, with testing between) it's OK.

It's also OK to use single doses for chlorine.