Stabilizer levels

[ShallowWater]

Maybe an equation will help -

FC = active chlorine + reserve chlorine

Active chlorine = hypochlorous acid + hypochlorite

Reserve Chlorine = chlorine that is bound to cyanuric acid.

When you have no cyanuric acid in the water, all of the FC is active chlorine. At a pH of 7.5, the amounts of hypochlorous acid and hypochlorite are roughly equal. So an FC of 1ppm is equivalent to 0.5ppm hypochlorous acid and 0.5ppm hypochlorite. Hypochlorous acid is the stuff that kills everything in the water and oxidizes bather waste. If you could hold hypochlorous acid in your hand it would burn a hole through your skin, the vapors would melt your corneas and it would likely explode. Hypochlorite is the stuff your laundry bleach is made out of. Makes you whites white and cleans your clothes.

When you follow the TFP recommended FC/CYA ratio, something like 90% of the chlorine you add to the water stays bound to CYA. The rest of it is free to form active chlorine. So your active chlorine compounds are more like 0.05ppm each.

Which scenario do you think is preferable ?

Hint - it only take about 0.1ppm active chlorine concentration to kill most pathogens and keep algae from growing.

Ran across this searching for something else. Sorry to open an old thread but which scenario ia better?

 

[ajw22]

When you follow the TFP recommended FC/CYA ratio, something like 90% of the chlorine you add to the water stays bound to CYA. The rest of it is free to form active chlorine. So your active chlorine compounds are more like 0.05ppm each.

 

[JoyfulNoise]

It is ALWAYS better in a residential outdoor pool to have CYA in the water where chlorine is held in reserve. Zero CYA doesn’t work in actual practice without serious amounts of highly automated measurements and dosing as well as constant filtration.