Using cal-hypo temporarily for daily chlorination


Active member
Oct 17, 2018
Southern Kentucky
I can’t find any liquid chlorine in my local stores so I was thinking about using cal-hypo for daily chlorination until our pool service comes to close our pool on Friday. We plan on closing at half shock level since we are using polyquat at closing so I will just be using the cal-hypo to keep FC at half shock level until closing. I have never used Cal-hypo before so I have a few questions.
1. Is it necessary to dissolve it in a bucket before adding it to the pool or can I just dump it in the deep end and brush well afterwards, since I won’t be adding much at one time?
2. Does cal-hypo increase PH? I’m out of muriatic acid and I’m closing on Friday so I don’t want to use it if it might increase the PH.
3. What is the shelf life of cal-hypo and how can you tell if older cal-hypo is still good? I‘ve got 3 one-pound bags in my garage that are probably 3 years old that is like to use, if possible. There appears to be no clumps inside, but the outside packaging is very faded from being in the garage the last 3 years.


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
1. No. It will dissolve in the water. Do brush any granules that make it to the pool surface.
2. Yes, very slightly.
3. If kept dry, a very long time.