My CYA Changed

Kubota364

Member
Oct 11, 2021
9
Baton Rouge, LA.
Pool Size
16000
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
How did my CYA get so high without adding any? I noticed above this could be the reason of my low chlorine in the pool. I know my salt system isn't working right but I've been supplementing with tabs. Any ideas? TIA

FC 0
PH 7.7
Alkalinity 90
Cya 140
phosphates 0
Salt 3700
 

PoolStored

Gold Supporter
Jun 24, 2021
566
Ashtabula, OH
Pool Size
31000
Surface
Vinyl
Chlorine
Liquid Chlorine
How did my CYA get so high without adding any? I noticed above this could be the reason of my low chlorine in the pool. I know my salt system isn't working right but I've been supplementing with tabs. Any ideas? TIA

FC 0
PH 7.7
Alkalinity 90
Cya 140
phosphates 0
Salt 3700
For every 1ppm of FC added by a "tab," you are adding .6ppm of CYA. Tabs have CYA.
 
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Mdragger88

Bronze Supporter
Jun 1, 2018
3,135
Hernando, Ms
Pool Size
26000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
use PoolMath effects of adding to see all the consequences of a specific chemical on your water
You need to use liquid chlorine to supplement fc to prevent adding more cya to the water.
 

Kubota364

Member
Oct 11, 2021
9
Baton Rouge, LA.
Pool Size
16000
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
See this -->FC/CYA Chart

It will be very difficult to maintain sufficient FC unless your cell is sufficiently oversized.

You should consider replacing 50% of your water, which will get you to 70 CYA. Draining, Further Reading
Ok I can do that, I'll have a new cell on the way soon. Its the t15 and my pool is only 16k.
 

Newdude

Gold Supporter
TFP Guide
Jun 16, 2019
11,173
NY
Its the t15 and my pool is only 16k.
Sweet choice. Per poolmath it will make you 3ppm in 6.5 hours of 100% runtime. That will help longevity greatly only needing to run it 1/4 of the day more often than not.

Sweet ROI too. The T3 ($349) costs half of the T15 ($699) but makes about 1/3 the chlorine. (.53 to 1.47). So you’ll get almost 3X the lifespan for only double the cost.

The T9 ($549) falls somewhere in the middle being .98 lbs a day. Still a bargain long term but not as good as a bargain.
 
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Mdragger88

Bronze Supporter
Jun 1, 2018
3,135
Hernando, Ms
Pool Size
26000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
Are those results from your testing or a pool store? You need an accurate result from a proper test kit
Test Kits Compared
before you make such a large change.
Pool store cya tests are known to be flawed.
When u get your kit in you will need to do the diluted version of the cya test.
step 8👇
You don’t want to go through all that draining & refilling only to find out you drained too much or not enough.
With cya so high & a fc of zero for any length of time you likely now have an organics problem which will require a SLAM Process
A cya between 30 & 60 is ideal for this otherwise you use alot more liquid chlorine.
To rule out organics do an Overnight Chlorine Loss Test
All of these things require a proper test kit.
 
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Kubota364

Member
Oct 11, 2021
9
Baton Rouge, LA.
Pool Size
16000
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
Are those results from your testing or a pool store? You need an accurate result from a proper test kit
Test Kits Compared
before you make such a large change.
Pool store cya tests are known to be flawed.
When u get your kit in you will need to do the diluted version of the cya test.
step 8👇
You don’t want to go through all that draining & refilling only to find out you drained too much or not enough.
With cya so high & a fc of zero for any length of time you likely now have an organics problem which will require a SLAM Process
A cya between 30 & 60 is ideal for this otherwise you use alot more liquid chlorine.
To rule out organics do an Overnight Chlorine Loss Test
All of these things require a proper test kit.
Those levels are from my Taylor test kit but I can take a sample to my local pool store and compare. Thank you.