CYA levels in 3 month old pool

Stevo2440

Member
Apr 17, 2020
5
Pearland Texas
New Plaster pool. First season. I use trichloride tabs in a chlorinator. My Cl levels were way high at first. Got a Taylor Test kit and now have that under control. Recently tested the CYA level and was 80. I know it’s in the high level, but Is it that high? Is it possible I got it that high in such a short time? Don’t want to get to Cl lock. Am I overreacting?
Thanks in advance.
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
12,670
Houston, Texas
Hi, welcome to TFP! You are not over reacting! You need to stop using trichlor/dichlor as it will add CYA. It is best to use liquid chlorine so your CYA doesn't get any higher. Check out this video for more on the chlorine/CYA relationshipl.
 
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JJ_Tex

Bronze Supporter
Jul 17, 2019
1,725
Prosper, TX (DFW)
There is no "lock" but, higher your CYA, the higher you need to keep your Free Chlorine (FC) levels. Check out the FC/CA chart in my signature.

At 80, you should be keeping your FC at 7+. That is fine, but people get into problems when they try to keep their pools at a FC of 3 regardless of their CYA.
 
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zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
12,670
Houston, Texas
CYA degrades very slowly. Draining some of the water is the only practical way to lower CYA levels. If you can get 10% liquid chlorine that would be best. You can find it at Walmart, pool stores, and big box hardware stores. If you can't get 10%, you can use 6% plain, unscented bleach from the grocery store.
 
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Stevo2440

Member
Apr 17, 2020
5
Pearland Texas
CYA degrades very slowly. Draining some of the water is the only practical way to lower CYA levels. If you can get 10% liquid chlorine that would be best. You can find it at Walmart, pool stores, and big box hardware stores. If you can't get 10%, you can use 6% plain, unscented bleach from the grocery store.
Would you recommend draining it myself? Or should I get a pro? My app I use suggests 33%
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
11,041
Franklin, NC
Would you recommend draining it myself? Or should I get a pro? My app I use suggests 33%
CYA of 80 is not an "emergency"

If you switch to using liquid chlorine no need to drain at this point. Just raise your FC levels to take the higher CYA into account and bring the CYA down slowly. For a CYA fof 80 just keep your FC in the 9 - 11 range. Yes, it's safe to swim.


When I took over my pool the CYA was 250ish... I had to keep the FC around 20 most of the time. It took me about 18 months to work it down to a reasonable level.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,930
San Dimas, CA (LA County)
CYA of 80 is not an "emergency"

If you switch to using liquid chlorine no need to drain at this point. Just raise your FC levels to take the higher CYA into account and bring the CYA down slowly. For a CYA fof 80 just keep your FC in the 9 - 11 range. Yes, it's safe to swim.


When I took over my pool the CYA was 250ish... I had to keep the FC around 20 most of the time. It took me about 18 months to work it down to a reasonable level.
This.

You can maintain it easily at 80 CYA but be extremely careful about maintaining adequate FC and about brushing. You really don't want to get algae. If you do you'll pretty much have to drain, ready or not.
 

Stevo2440

Member
Apr 17, 2020
5
Pearland Texas
This.

You can maintain it easily at 80 CYA but be extremely careful about maintaining adequate FC and about brushing. You really don't want to get algae. If you do you'll pretty much have to drain, ready or not.
Yeah I’ve got some light yellow spots that I’ve been brushing. I think it may already be there. Goes away easily but come back a few days later. I shocked it and they’re still coming back. My Cl has been around 5-6 so it makes sense.
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
11,041
Franklin, NC
Yeah I’ve got some light yellow spots that I’ve been brushing. I think it may already be there. Goes away easily but come back a few days later. I shocked it and they’re still coming back. My Cl has been around 5-6 so it makes sense.
Gotta bring that up to 9 - 11.

Our whole system is based on maintaining the correct level of FC in ratio to the CYA that's in the water.