best guess question

[dansdad]

Confused here if fc is 4 then shack at 12? What??? 12 what? thanks dave

[CarlD]

OK: First off, other than pH, all levels in all tests are measures of Parts Per Million, or PPM. IF you are fighting algae or for some other reason need to sanitize your pool extra ("Shock" it) you select the ideal Shock value from the Best Guess table based on the level of Stabilizer in the water. Stabilizer is also called CYA (for cyanuric acid). That's a different test.

Once you have your current CYA level, the Best Guess table gives you both the SHOCK level of chlorine to clear your water, and the NORMAL range of chlorine to maintain your water. BOTH are measures of FC (Free Chlorine)

So, suppose your CYA level 40 (ppm). You SHOCK your pool by raising FC to 15 (ppm) and keep it there until it's clear of algae and doesn't drop rapidly from 15ppm. Once that happens you can slowly (via just using your pool) let your FC level come down to the 3ppm to 6ppm range, never letting it get below that. If it gets a bit low, you add chlorine to raise it back to 3-6.

[dansdad]

ok so I will get my cya level then measure from there to keep pool clean ok Thanks Carl

[CarlD]

ok so I will get my cya level then measure from there to keep pool clean ok Thanks Carl

Yup! You CAN take a sample to a pool store, but the Taylor test in your kit is easily more accurate. Do NOT try to get a reading off test strips. I have the ones, several brands, with CYA tests on them and I am D****ed if I can EVER get even a vaguely accurate read for CYA.

Here are some tips though for the black dot test:
1) Do it the same way every time. While different people get different results, doing it the same way means your measure of CHANGES in CYA will be accurate.
2) The exact amount of mix in the squeeze bottle isn't nearly as important as making sure the mix is 50/50 water/reagent 13.
3) Don't forget to shake the mix for at least 30 seconds before running the test.
4) I always hold the vial at waist level facing into the sun and SLOWLY add the mixture till I cannot see the black dot, even slightly moving the vial from side to side.
5) Re-run the test several times. The beauty of this is ALL you need to do is pour the mixture back from the vial into the squeeze bottle, and then run the black dot test again. I ALWAYS do it at least twice. Doesn't hurt to shake the squeeze bottle again.
6) Remember: Halfway between 40 and 50 isn't 45--it is a logarithmic scale, so try to adjust, but realize anything between lines is a guess.

Hope this helps.

[dansdad]

No Carl I have the 2006 and used it last year but it still got ahead of me ( algae) I am going to be more diligent this year starting NOW. I just didn't know how early I should start. Going to w mart to pick up many many gallons of bleach. Why would I need polyquat if I stay on top of it? Just wondering Thanks Dave

[CarlD]

Step one: Since you have a 2006 take a FULL set of tests and post them here. That's the first thing: Know what's in your water.

[dansdad]

Carl my readings are
cl 0
ph 7.0
alk 6
cya black dot never covered

I put 2 levels of powder then 4 then 6 finally 7 and it became a mild pink
took one drop to go clean

pool is still clear weather is still cool

[CarlD]

OK. That helps:
When you ran the chlorine test, you were running the FC test. Did you then, using the same water, run the CC test? You then add (I believe) reagent #3, and if IT turns pink,you follow the same process to determine CC. FC+CC= TC--Total Chlorine. You have 0-.5ppm of FC.

pH is a tad low, but OK for a concrete pool, closed.

Alk = 6 makes no sense. You should not be able to get a reading below 10.

CYA: You have none.

Since you are in winter mode, you want to get your FC to 10 as the shock level. You can use just bleach to do this. 1 gallon of 6% bleach should add 4.6ppm of FC, 1 gallon of 8.25% will add about 6.3ppm of FC. Adjust accordingly.

Since your pH is low, I would not use Tri-Chlor tablets to chlorinate unless you first raise pH with Borax.

[dansdad]

ok Carl I will adjust and get back

[CarlD]

Good luck with it!