Determining CYA level benefits

[calstar]

What, if any, is the advantage of a 40 or 50 CYA level over one of 30(my pool)? The higher CYA levels require higher FC, but do they protect the higher level FC better , is there a disadvantage to using the lower 30 CYA level. For example, will there be more FC loss( %) at a level of 30 than loss at level of 50? thanks

 

[Texas Splash]

What, if any, is the advantage of a 40 or 50 CYA level over one of 30(my pool)?

You said it protection from the summer UV that is typically much more intense in the summer. I can't speak for the Santa Barbara area itself, but in places like Vegas, Phoenix, etc, if you don't have a CYA of at least 50 or even 60 in some cases, and the pool gets a lot of sun, the FC will not make it form day to day. So it all depends on those exposure factors.

Possible disadvantage (of a lower CYA) .... faster loss of FC to the point that in a 24 hr period the FC could fall below the recommended level and allow algae to grow.

The biggest exception to all of this - an indoor pool or someone who keeps their pool covered all of the time.

 

[calstar]

You said it protection from the summer UV that is typically much more intense in the summer. I can't speak for the Santa Barbara area itself, but in places like Vegas, Phoenix, etc, if you don't have a CYA of at least 50 or even 60 in some cases, and the pool gets a lot of sun, the FC will not make it form day to day. So it all depends on those exposure factors.

Possible disadvantage (of a lower CYA) .... faster loss of FC to the point that in a 24 hr period the FC could fall below the recommended level and allow algae to grow.

The biggest exception to all of this - an indoor pool or someone who keeps their pool covered all of the time.

Thanks, that answered my question, I lose about 2 ppm FC a day at 30 CYN in the full summer sun(latitude 34), I'll bump it to 40 and see how that goes.

 

[sande005]

I spent too much time in "The Deep End" here, reading things I don't understand. But I think the gist is that CYA, beyond shielding FC from UV rays, acts as a mild reservoir for it - so as the active gets used up, a little more becomes freed up from the CYA, to help. So having higher cya (to an extent) helps in two ways to reduce the amount that gets used during the day. We have to keep adding, because the end product doesn't disappear, but is ineffective - and the CYA reservoir also gets replenished. But others will be able to set me straight if I got it all wrong.....