Question on test results

[Lauriebobby]

20k gallon salt water pool. TF-100 test results:
FC 5.5
pH 7.5
TA 90
CH 300
CYA 25

does it make any sense that my FC is on the high end of normal while my CYA is low? My pool is clear and blue - should I be adding more stabilizer based on the numbers?

thanks!

 

[Lauriebobby]

20K gal, hybrid, 3.4 sqft StaRite sand filter, AutoPilot Digital SWG

 

[Newdude]

CYA always rounds up so you are at 30 if your test method is a reliable one. Being as far north as you are 30 is probably enough. It wouldn’t be in the hot climates.

 

[PoolNewb2020]

If your SWG has no problems generating FC and keeping up with demand, without it running 24/7 and at or near 100%, then your CYA level is fine.

Also, running the FC levels on the high side is preferable as it adds a safety margin for things like excessive rain, swimmers, etc. There is little benefit of running the FC on the low end of the scale.