This has probably been posted before and prob how TFP balance rules were established...but I found the background details useful and how CYA "holds" the FC.
New Thinking: Chlorine/Cyanuric Acid In Balance - AQUA Magazine
Couple of thoughts:
-It states that general rule is 7.5% FC to CYA level which produce slightly lower FC targets then the TFP chart (ie 7.5 FC ppm to 100 CYA etc).
-Also the takaeaways at the end of the article I found helpful especially about how the higher CYA levels buffer organic killing power of the FC but at the same time make the higher FC levels as "Safe" to swim as lower FC levels w/ lower CYA levels. For example my wife was worried that I was keeping our FC levels too high (8 w/ CYA at 70) and that they were higher then the 4-5 safe limit set by fed standards, but as stated in article that 4 ppm limit was based on zero CYA. This is implied in the FC/CYA charts but it was good to get more details on why the higher FC levels were safe.
New Thinking: Chlorine/Cyanuric Acid In Balance - AQUA Magazine
Couple of thoughts:
-It states that general rule is 7.5% FC to CYA level which produce slightly lower FC targets then the TFP chart (ie 7.5 FC ppm to 100 CYA etc).
-Also the takaeaways at the end of the article I found helpful especially about how the higher CYA levels buffer organic killing power of the FC but at the same time make the higher FC levels as "Safe" to swim as lower FC levels w/ lower CYA levels. For example my wife was worried that I was keeping our FC levels too high (8 w/ CYA at 70) and that they were higher then the 4-5 safe limit set by fed standards, but as stated in article that 4 ppm limit was based on zero CYA. This is implied in the FC/CYA charts but it was good to get more details on why the higher FC levels were safe.
