Fc to cya

[Pete23]

The Cya in my pool is at 150 it's gone up substantially from 75-100 in a couple of days (Ive heard the chlorine tablets can do that). Anyway should I raise the fc in the water? Cdc recommends 1-3ppm and at least 2 if the Cya is high? Right now fc is at 5ppm. Thanks for the help in advance.

 

[bobodaclown]

OMG! Yes.... You're really high enough to do a partial drain and fill.
Have you seen this CYA/FC relationship chart? Pool School - Chlorine / CYA Chart

You may want to visit pool school: Pool School - Getting Started

 

[fajitas21]

I'd say a few days of 50 cya ppm increase is more than tabs too. In other words, Tabs + a powered shock w/ CYA in it, or accidentally adding Stablilizer. One more, the CYA tests aren't the easiest, but easy enough with the Taylor and TFT kits, but they must be done properly. Maybe just a testing mixup? On average, a 3" Trichlor puck will add about 3ppm CYA per week to your pool if dissolved. There is plenty of wiggle room there, but what I'm getting at is if you jumped it that high that quickly, there's a lot of tabs in there, or a powered "shock" product containing stabilizer, or both.

 

[Pete23]

I was going to do a drain soon, but it's 90 today and the weather wasn't going to last is it OK to swim in?

 

[bobodaclown]

Sure.