trying to raise cya

Cheryl B

May 24, 2019
Spring, Texas
New to using Muriatic acid and bleach. Have refilled hot tub several days and using poolmath for calculations. Our biggest problem is PH (8.4 out of the tap) and TA - started at 177 and is now 66 with a PH of 8. Presently running all jets with cover off.
My CH and FC are normal, but my cya is still only 7.
Can you explain this to me: " For every 10ppm of chlorine using Dichlor, your CYA will increase by 9ppm. " Nitro has said it is easier to calculate what you need and add it, as the measurement of cya is often inaccurate. The "7" was done by the pool store. How do I calculate dichlor ppm?
FC is 3, and calcium hardness is 125.
Thanks for any help! Cheryl B


Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
Tucson, AZ
:wave: Welcome to TFP!

In PoolMath you can enter the weight of the Dichlor you added and it will calculate the amount of FC and CYA it adds.

This is in the effects of adding chemicals section.