Won’t register chlorine

  • Last Post 04 July 2021
Conroe posted this 04 July 2021

Just recently drained 2 ft of water from my 17,000 gal pool due to cya above 100 . Leslie’s says my cya is now in normal range at 82, but now no matter what I do liquid chlorine tabs or shock I can not get a chlorine reading above 0.06 free chlorine. 

My current free chlorine is 0.06 and total chlorine is 0.09

Ph 7.8, alkalinity  76, phosphates 0, calcium hardness 400, 

I’ve never in 8 years ever had these issues. No matter what I do or put in my chlorine is nonexistent. 

Your site says I can call you buy can’t find a phone number. Can you help?

JCMC70 posted this 04 July 2021

Hi Conroe

The people at Leslie's are incorrect. The recommended level for CYA is 30-50 ppm. So your CYA level is still too high. 
As an example, in pool water with 40 ppm of cya the chlorine level should be maintained at 3-7 ppm with 3 ppm being the absolute minimum and 5-7ppm being the target range for proper sanitation.

In pool water with 80 ppm of cya, the minimum free chlorine level should be 6 ppm and the target level is 9-11 ppm to achieve adequate sanitation.

As the cya level rises, you need higher levels of free chlorine to sanitize the water. I don't know what level of chlorine you are bringing your pool up to but it probably isn't high enough for the cya level.

CYA levels above 70 ppm are not recommended because of the amount of chlorine it takes to sanitize the water.

You need to either drain some more water and get the cya level down or bring the free chlorine level to the recommended amount for the cya level in your pool.

Once you bring the free chlorine level to the amount needed, if the water still doesn't hold the chlorine level, you've got organics growing in the water that will require super chlorination to kill.