FC and CYA- am I doing this right?


Gold Supporter
May 31, 2020
Dallas, TX
New pool, initially had CYA of 0 and FC 1-2, with running SWG almost all the time at 100%.
I added CYA-stablizer (about 2/3 the recommended amt per pool math) and 2 days later my CYA level was 20, but my FC with up to 20 also!
Still very high after cutting back the time and % on the SWG and so I turned in off for 2.5 days, and now it is at around 6-7.
I turned the SWG back on to 60% 12 hours a day.
pH is around 7.8 (had been higher but came down without me adding anything).

Question - is my next step to add more CYA to get that level up to 60? Am I correct in thinking that will raise my FC higher and I will need to cut back further on the run time/percent with my SWG?
Is it better to cut back on the run time for the SWG or the %?


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
As long as your pool is crystal clear and no algae, raise your CYA to 60-70 ppm.

Set your SWCG to generate 4ppm FC per day. Poolmath can guide you on that. Or let us know how many hours you wish to run the pump and we can tell you what % to set it.