CYA going high and high

kenjo

Member
Jun 24, 2020
6
New Jersey
5 days back I thought to test water from pool supplies store, so I went with water sample and came to know that CYA is 125 out of my 28000 gal pool. So person suggested me to drain 1ft of water, so I drained and refill 1.5 feet and then went back for testing. This time FC was low and CYA came down to 120. Suggestion I got after water test - add 3 lb of Chlor-bite (dichlor) and keep filter running. then I went back next day for third test and strange CYA went up to 135 and FC was 2.6. Suggestion came to drain again to 2 feet.

I am not sure what causing CYA going high, I do not have anything added but Chloro-bite.

Any suggestions?
 

JJ_Tex

Bronze Supporter
Jul 17, 2019
1,725
Prosper, TX (DFW)
Welcome - you have 2 things working against you:

1. Pool store tests are inconsistent and designed to make you buy something
2. The trichlor adds CYA, as do most non liquid chlorine products. I did the math, your 3lbs raised your CYA by 7. Still a lot, but not the 15 your pool store said, which leads back to point #1.
 
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Chasarms

Silver Supporter
May 8, 2020
347
Dardenne Prairie, MO
Dichlor has nearly as much CYA, in terms of ppm, as it has chlorine. The Chlorine is lost, the CYA stays.

The only way to add Chlorine without adding CYA is to use liquid (sodium hypochlorite), Cal hypo, or a salt water generator. If you have calcium concerns, cal hypo may be a bad choice.

CYA will burn off or splash out over time, but it takes a while. Draining only a foot is not going to help much, as you discovered. It's pretty straight math. If you want to cut CYA levels in half, you gotta replace half of the water.
 

Chasarms

Silver Supporter
May 8, 2020
347
Dardenne Prairie, MO
I will check water after refill completes and then will check things on my own before going to pool. Liquid chlorine - bleach would help?
It would help in that you can keep the pool chlorinated and sanitized without adding any CYA. Note that with CYA levels that high, you will have to keep a very high PPM of chlorine in the pool to prevent issues, and if you do have algae, SLAMing the pool will be a challenge with those CYA levels.
 

JJ_Tex

Bronze Supporter
Jul 17, 2019
1,725
Prosper, TX (DFW)
Liquid chlorine or bleach only have chlorine in them, so you are not adding CYA. Most people on here who don't have salt water pools use liquid chlorine almost daily, and save the tabs for when they go out of town.
 

Chasarms

Silver Supporter
May 8, 2020
347
Dardenne Prairie, MO
@Chasarms Thanks. Currently pool is like crystal clear and no foggy - no algae. I will try to keep high ppm of chlorine in that case

For reference:

 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
1,577
Spring Valley, NY
@JohnT I felt same. Looks like college students or because of current situations they are keeping less expert people.

I am planning to buy - https://www.lowes.com/pd/Pool-Essentials-1-Gallon-Liquid-Pool-Chlorine/1000181271 to maintain FC level without touching CYA.
Kenjo,
That's the expertise pool stores offer and they're one in the same. Can you please fill in your signature with the link below and let's get a full set of test results so we can see what you have going on assuming you have one of the recommended test kits.
 

Coverdog

Member
Sep 12, 2015
18
SW Florida
I would never trust a pool store for advice or testing. I have a pinch a penny and leslies pool a mile from my house. Just for chuckles I took the same water sample to both stores on two occasions. There tests were not even in the same ball park as each other and not close to my tests. I only trust my own tests.
 

kenjo

Member
Jun 24, 2020
6
New Jersey
Tests (At Leslies Pool)
06/19/2020 - FC 0.1, pH 7.5, TA 54, CH 149, CYA 127
DRAIN 1.5 feet water and refill
06/22/2020- FC 0.14, pH 7.6, TA 67, CH 161, CYA 120
ADDED 3lbs Cholo-bites (Diaclor)
06/23/2020 - FC 2.06, pH 7.5, TA 61, CH 220, CYA 135
DRAIN 3 feet water and refill
06/24/2020 - FC 0.47, pH 7.8, TA 87, CH 168, CYA 102
 

mguzzy

Gold Supporter
Jul 8, 2015
2,388
OV, CA
You are getting closer.. you still need to drain more than half your water to get to a CYA of 30-40. 102 is still very high. Assuming the pool store is correct, which we know is suspect. SOooooo, you need to get your own test kit. The forum has standardize on a particular test reagent that we know how it works. The Taylor K-2006C or even better the TF-100 also uses Taylor reagents but has better proportions for home pool testing. You can get it here tftestkits.net. Check this out: Test Kits Compared While you are at it get the stirrer.. it makes it a lot easier.

Once you get your test kit post a set of numbers and we will proceed from there!