I believe I over stabilized

tombo

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Aug 1, 2010
2
My Ph is 7.2, CYA is 120+, FC is very low. My neighbor told me that I could add as much stablizer as I wanted, you couldn't add too much. Unfortunately I believe I over stabilized and the excess CYA is grabbing all the chlorine I keep adding. Is my only alternative to pump down the pool water and add new water to lower the CYA to 70ppm and then add appropriate amount of chlorine?
 

duraleigh

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Apr 1, 2007
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Re: Chemical numbers - request advice

Hey, tombo,

Welcome to the forum. :lol: One of the moderators will soon move your post to it's own thread (Done. JasonLion) so post back if you can't find it. Essentially, the answer is yes, your only alternative is to partially drain and then refill.
 

Bama Rambler

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Welcome to TFP.

How are you testing?
As Dave (the other Dave) said, if your CYA is too high there are only two reliable ways to lower it. Drain & refill or R/O (reverse osmosis).
 

lightingguy

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Jun 17, 2010
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Glendale, CA
Keep in mind - even with high CYA you should be able to maintain and test for a high FC count. The CYA wont hide the chlorine from the test.

If you are struggling to keep your FC level up - then something else is gobbling up the chlorine.

If you post a set of numbers and more detail on your situation ppl can get more specific with the advice.
 

JasonLion

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As lightingguy said, CYA doesn't "grab" chlorine, there has to be something else in the water consuming chlorine (most likely algae). The problem with high CYA levels is that they make it nearly impossible to kill off the algae and get back to normal conditions. You need to get the CYA level down, then shock, and then things will be alright after that.
 

tombo

New member
Aug 1, 2010
2
Thanks for the advice.
I will try and recount the time line of my pool problem. I had some cloudy water, slight visible algae at the tile line, and slight slime on the shaded side of the pool. I brought my water in to the pool store several times and they said it was OK. I finally told them it was still cloudy and they said to shock it. I used 4 lb of super quick shock and it cleared up significantly but still not clear. My neighbor suggested I add stabilizer and said more is good, you can never have too much. In the last month I added over 8 lb to a 12,000 gal gunite pool. During the last week I added 3 gals of liquid clorine and 2 lb. of fine powder chlorine while running the ctg filter pump all night long (13 hrs +) for 5 days. The pool finally cleared up, no sign of any algae and no slime on the shaded wall, but the FC was very low on the strip test and undetectable with my liquid drop tester. I tested FC right after the addition of the 2 lb. solid addition last thursday night and the FC was very high on the strip test but early the next morning it was very low again. I have removed at least 1/2 of the water and will begin refilling shortly. I plan to retest the water after filling and adding chlorine as needed and balancing the PH with acid to lower or soda ash to raise.
 

JasonLion

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You haven't actually killed all of the algae. You only killed the obvious visible algae. But there is still more in the water. At very high CYA levels it takes way way more chlorine than you used to kill all of the algae. You should read How To Shock Your Pool for the full procedure for getting rid of algae.
 

anonapersona

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Nov 5, 2008
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tombo said:
My Ph is 7.2, CYA is 120+, FC is very low. My neighbor told me that I could add as much stablizer as I wanted, you couldn't add too much. Unfortunately I believe I over stabilized and the excess CYA is grabbing all the chlorine I keep adding. Is my only alternative to pump down the pool water and add new water to lower the CYA to 70ppm and then add appropriate amount of chlorine?
Even CYA 70 is pretty high, you'd be better off to adjust it down to about 40 ppm. And I have to wonder if you are correct starting at 120. I see 4 lb of dichlor (super quick shock) and 8 lb of stabilizer (assume 100%) and 2 lb "fine powder chlorine" which I have no idea what it is so let's assume also dichlor. Then "2# lb solid" which I have no idea what that is either so let's assume dichlor powder.

So total 8 lb dichlor and 8 lb stabilizer. Putting that into the Pool Calculator, at the bottom where it says Effects of Adding Chemicals... first add pool volume at the top, then the stuff added at the bottom.... CYA 40 from trichlor and CYA 80 from stabilizer, plus whatever was in the pool before. So yeah, CYA 120 if it was zero when you started, otherwise much higher.

Given that the stabilizer may not be all showing upon test yet, you ought to shoot for a CYA of 30 and drain and refill 75% of your pool. That way if some of the stabilizer has not yet shown up on test, you may be left with more than 30 but it probably won't be more than 50. This has to be done in one drain and refill cycle, no going partway and refilling then doing it again since that will drain off some of the new water with the old.

Double check the figures above with the actual chemicals you used as I have made some assumptions there.

AND read Pool School.
 

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