Recommended CYA levels for SWG pools of 70-80 ppm too high?


New member
Sep 12, 2017
Bloomington, IL
Anyone read this article on CYA levels?

They cite the CDC and share that, "In case of a fecal incident ... CYA levels can no longer exceed 15ppm.

Here’s why: chlorine stabilizers (like CYA) slow the rate that free chlorine kills pathogens. Because of the slowed rate of sanitation, pools must have below 15ppm CYA when treating a fecal incident. That way, chlorine can sanitize effectively in a reasonable amount of time."

Thoughts on this? How might this standard apply differently to SWG pools?


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Government pool standards have not been updated in over 30 years as science has gained new insights in pool water care.

The source of that article is not objective. They have a product to sell.


Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
Franklin, NC
First, this is an article written by a company trying to sell products. It seems to play fast and loose with what the CDC actually says. Reading the only CDC document I can find that has a 15ppm notation on CYA, it appears that they recommend reducing the CYA to 15 or below when dealing with a fecal "incident". It doesn't say there is a hard rule on 15ppm on CYA

Second, there is no reliable way to test CYA below about 20, so it is kind of ridiculous on its face.

Third, it is a recommendation, not a requirement. Rules are written by local jurisdictions, not the CDC.

Fourth, it says what we have been saying all along - CYA in the water reduces the ability of chlorine to do it's thing. So, you can either lower the CYA like they recommend or, get this - raise the FC level to compensate for the amount of CYA in the water. This is exactly why we have the FC/CYA Table