FC (free Chlorine)

[SetteWm07]

Hi,

First time on the site. So far I find it very informative. Can you tell me what it means if my suggested FC level on the Pool math calculator says 4 to 6. Does this means 4 to 6 ppm's. If so, that seems very high compared to what my Taylor test kit suggests. Can someone help me clarify this? Thanks.

 

[Casey]

Welcome to TFP.

It means PPM. Your FC works with your CYA/Stabilizer levels. You can read about that in here :lookhere: Pool School. I would suggest :lookhere: ABC's of Pool Water Chemistry and Recommended Levels.

 

[JasonLion]

Welcome to TFP!

Yes, 4 to 6 means 4 ppm to 6 ppm.

Most sites/products continue to repeat FC level recommendations from before CYA was discovered/understood. Without CYA it is very important to keep FC fairly low. But once there is CYA in the water everything changes dramatically. CYA binds to chlorine and makes much of it inactive/held in reserve. To maintain active chlorine levels that are high enough you need to have a higher FC level.