CYA

[feetr2c]

So why do you guys recommend an ideal range of 70-80 for CYA, when anything over 50 greatly reduces the sanitizing ability of FAC and therefore requires greater amounts of chlorine, thus making the SWG work longer and therefore harder??

 

[splashpad]

My understanding is the FC is constantly added via the chlorine generator.

 

[Richard320]

So why do you guys recommend an ideal range of 70-80 for CYA, when anything over 50 greatly reduces the sanitizing ability of FAC and therefore requires greater amounts of chlorine, thus making the SWG work longer and therefore harder??

It requires greater amounts of chlorine to get to the minimum, but maintaining it once it's there is pretty much the same, so there's no huge strain on the SWG. The higher losses from the higher concentration of chlorine are offset by the greater protection from the higher CYA.

If you're able to decipher the graphs and technical talk, Pool Water Chemistry probably has the answer.

 

[IceShadow]

From the FC/CYA Levels article:

Most saltwater chlorine generator (SWCG) pools appear to remain algae-free at a lower minimum FC level compared with the minimum FC column for manually dosed pools. This may be due to the high chlorine level within the cell.

 

[mguzzy]

Also from the article with all the graphs and tech talk:

Salt Water chlorine Generation (SWG) pools seem to require a higher level of CYA, about 70-80 ppm, to operate efficiently. The theory is that the CYA is slow to "store" the chlorine as it is being generated so without enough CYA there is a build-up of chlorine that degrades the performance of the salt cell.

And I can attest to that. My FC retention seems to be best as it approaches ~70ppm CYA and then it levels off at higher CYA concentrations.