Is CYA really needed?


Well-known member
Oct 18, 2016
Long Valley, NJ
Just installed a SWG this year. Have been running for about three weeks and the water has looked amazingly clear the entire time, with no signs of algae forming on the walls or anything. So far, I'm VERY pleased.

Per this site and the SWG instructions, I started adding granular CYA to the pool (via stocking in the skimmer) since it was at 0. I'm having a heck of at time getting the it to dissolve. So far, I've only been able to raise my CYA to about 20.

My question is, do I really need the CYA? Like I said, the water looks amazing, and my chlorine tests have been consistently holding in the 3-5 ppm range, and I'm only running the SWG at 40% (it's a 60K gal SWG on a 30K gal pool).



Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
Yes. But, the level is up to you. We recommend a higher level CYA for SWCG for several reasons. One is economics. But if that is not a concern, run a lower CYA. But, do not run too low, as the FC being protected by the CYA is a reserve, for that time some guests in the pool add some unexpected organics, or a flock of birds use your pool, or whatever.

Getting the CYA to dissolve should not be that hard. I hope you are swimming in your beautiful pool. Take the sock out while you are swimming and squeeze it in the pool. It should readily dissolve.


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
How much stabilizer have you added? To go from 0 to CYA 60 you need to add 232 oz of stabilizer. About 15 lbs.

If you put that amount in socks in the water and squeeze it frequently it will eventually dissolve.