Chlorine useage based on cya level ?

[mdhwoods]

My cya is about 60 and my chlorine range is 5-9. I use about 3 ppm a day and and 4.5cups a day to bring it back up. Left town Friday night and brought my pool up to shock level of 18. Figured when i returned Sunday night i would find a Chlorine level of 12. Returned and tested chlorine level and it was 8.5.

So my question is, if outside of your recommended chlorine range does your cya loose its ability to buffer your chlorine loss? Will i loose chlorine at a faster rate during the day when it is above 9 versus when it is between 5-9?

I also had a lot of rain so i am sure some of my loss was due to dilution. I had to drain several inches of water.

Thanks

 

[frustratedpoolmom]

Yes, and that sounds normal to me especially if the pool was left uncovered. Did you use a solar cover? Using a solar cover while your gone will slow down the loss significantly.

 

[JasonLion]

Chlorine lost to sunlight goes as a percentage of the FC level. With CYA around 60 you are losing about 1/3 of your FC each day, not 3 ppm/day. That means that when FC is 18 you lose 6 ppm the first day (approximately).

 

[mdhwoods]

Chlorine lost to sunlight goes as a percentage of the FC level. With CYA around 60 you are losing about 1/3 of your FC each day, not 3 ppm/day. That means that when FC is 18 you lose 6 ppm the first day (approximately).

Well that makes perfect sense. With it at 9 I loose 3 which leaves me at 6 under normal levels.