Do It Now?

joel0711

0
LifeTime Supporter
Apr 25, 2010
183
East Tennessee, 40 miles west of Knoxville Tn.
Pool Size
19000
Surface
Vinyl
Chlorine
Liquid Chlorine
Checked my CYA amount yesterday. Due to heavy rains I've drained some this week and test showed I've dropped from 40 to 25. With this week's forcast giving a chance of storms each day (30% to 70 %) should I wait until the weather is more stable to add CYA since it is best not to backwash for a week or so after adding CYA?? Using the amount given on the calculator of course.
 
I run my CYA at 50 and due to rain I've had to drain 3" of water so far this week, more rain forecast-ed for the coming week. I don't plan to retest CYA or add any till the rain stops. I normally run a FC of 9 ppm and it has gone up this week I guess from none use and no sun. If manually dosed I would just keep checking FC daily and add as needed.
 
Joel, assuming your pool is not terribly unusual, it has probably an average depth of 4 feet. If you lost 37.5% of Your CYA that means you had 37.5% of 4 feet in rain....18".

Unless you really did have that much rain, your discrepancy in CYA readings is at least part testing error in some form.

Anyway, recheck your CYA and the history of your CYA tests, If you have historically been at 40ppm and your tests really indicate a 25ppm, then I would suggest you bring it back to 40ppm and keep your FC 3-5ppm. Man, that is a lot of rain, though.

I think it would be penny wise and pound foolish not to bring your CYA up to it's normal level......one of the ideas in pool water management is consistency and chlorinating a pool where you allow the CYA to wander up and down is not consistent.
 
re-tested,, filled the tube 10 different times,,, average of 35 on the tube----- oops--human error again--- I had planned on testing a second time before I added any CYA. I'll leave it alone.

cCYA chart shows 5ppm chlorine as target level,,, I've been running 7ppm just to be safe.... Is this good insurance or just wasting chlorine??
 
The best number to watch is the minimum, rather than the target. Keeping your lowest FC level of the day 1 or 2 above the minimum is good insurance. For most people the minimum is reached in the evening. The target level is a guess at what you need to raise FC to in order to stay at or above the minimum, but the real target level varies from pool to pool and season to season, depending on many factors.
 
With pretty good assurance that your CYA is 35, I would suggest you calculate a dosage that will add 15ppm more to get to 50ppm. You don't even need to test for it because your present number is accurate and your dose will be accurate so you will be safe in assuming your CYA will be 50ppm.

Now,your target for FC is 4-6ppm, so dose the pool to attain 6ppm and then check 24 hours later to see how much FC you have consumed. Ideally, it will be about 2ppm so you can dose that 2ppm (calculated carefully, of course :lol: ) back into the pool and sort of use that as a baseline dose to keep your FC in the 4-6ppm range suggested.

Pretty much wasting chlorine when you dose to 7ppm and your CYA is only 35 but the only harm is some extra expense and I'm sure your pool is quite clear so it is good insurance, too.
 
Thanks duraleigh ,, I'll get my sock of CYA ready and do it this weekend. Weather is calling for storms most to this week and I'll be backwashing to lower the level. Never have checked my daily chlorine use, just set the liquidator for a certain level,based on test numbers, and left it alone. After I get my CYA done I'll turn off liquidator and run a 24hr. useage check to have that info too---thanks fellas!!
 
Never have checked my daily chlorine use, just set the liquidator for a certain level,based on test numbers, and left it alone.
Then I would continue doing that. You will likely have to dial it back a little once you add the last dose of CYA. Put the Liquidator in your sig so others will know how you chlorinate your pool.
 

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