Indoor Pool Shock

[CPO]

We had a FC reading of 2 and a CC reading of 3 on a 100,000 indoor pool with a great ventilation system. Yesterday, we added 10lbs of cal-hypo as we attempted to raise the FC to 10 to break point chlorinate and only reached a 7.5 today with CC of 1.75 after 22 hours. We cannot use CYA and never have. We shock at most annually, sometimes less for CC alone. Water is always clear as glass.

Now what?

We could add 4-5lbs more to reach the original goal of 10 FC, but will that help achieve the goal of 0 CC at this point? - I don't need to pool this week, but it's in use on the 15th.

 

[Isaac-1]

First of all there is no such thing a break point chlorination, it is a myth started by bad science backed up by bad math 40+ years ago.

Next question is do you use any type of supplemental oxidation (ozone, UV or MPS)? If you use MPS chlorine free shock it shows up as CC on the standard test which may be part of your issue. If you don't use some type of supplemental oxidation, maybe you should consider it, particularly if you are banned by outdated regulation there from using any CYA.

 

[CPO]

We use only cal hypo. Nothing else.