Anything to be concerned about?

[Edgie311]

Here are my #'s

TC=1.0
FC=1.0
CC=0
pH=7.6
TA=90
CH=350
CYA=100
Temp=85F
Clean and Clear

Gary

 

[JasonLion]

With CYA of 100 I would normally keep FC at at least 8. It is not generally a good idea to run with CYA that high. Many of the tests will report CYA as 100 even when it is much higher. It is better to run with CYA at 90 or below, perhaps well below 90 if you don't get all day direct sunlight. The best way to get CYA down is to replace water. If your level is really just 100 then it won't be that difficult, a 10% or 20% water replacement will do it.

 

[Edgie311]

what are the consequences of high cya?

 

[JasonLion]

The largest problem is that it is very difficult to measure CYA levels above 100 acurately. The best CYA test only goes up to 100 and shows anything higher than 100 as 100 so you don't know your true level with that test unless you are under 100. Other tests measure levels up to 300 but are nowhere near as percise, giving results that are +-30 or worse.

Also, the higher your CYA level the more chlorine you need to maintain an effective level of disinfecting chlorine. CYA binds to some of the chlorine, which protects it from sunlight, but also prevents the bound chlorine from working as a sanatizer. The percentage of the chlorine that is bound up with CYA goes up as the CYA level goes up. That is why you need to keep FC at 8 or above with a CYA level of 100. Likewise, to shock you pool with a CYA level of 100 you need to bring free chlorine up to 25, which is a lot of chlorine to have to handle.