Chlorine not dropping?

Hi, I'm new to the forum and received my new TF-100 kit on Monday. Used to use 6-way test strips, but this is WAY more fun! The kids love to "help" count as I add the drops for all the tests and watch the color changes occur. :-D

We have a 15x30 ABG, sand filter, 1hp pump. Pool was relocated here, from the MIL's house and set up last fall with new liner and then closed for the winter. The pool is in full sun all day until 7pm with a 12 mil clear solar cover.

My question is regarding chlorine usage, or rather lack of chlorine usage.

Last Friday I shocked the pool using 128 oz. liquid pool shock (Sodium Hypochlorite 12.5%) and added 1lb PH+. Readings on the test strip prior were FC-3, PH 6.8. I used the poolcalculator suggested amounts.

Readings this week using the TF-100 are:

FC - 8
CC - .5
ph - 7.5
TA - 150
CH - 230
CYA - 40

FC - 7
CC - .5
ph - 7.5
TA - 120

FC - 6
CC - 0
ph - 7.5
TA - 110

I have added no chlorine, since shocking on Friday. Shouldn't the FC chlorine level be dropping more than 1 ppm per day being in full sun? Does Sodium Hypochlorite 12.5% add any CYA?

Pool was a nice 86-88 degrees tonight, just the way Mom likes it! :lol:



Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
Sebring, Florida
Hi, Michele,

Welcome to the forum. :lol: Those are absolutely very thorough test results. YOu are wise beyond your newbie status!! :lol:

My assumption is you are keeping the solar cover on your pool. That would explain your FC loss being held to 1ppm. Is that the case?

No, Sodium Hypochlorite does not add any CYA. Actually, that's why it is the best thing with which you can chlorinate your adds nothing to your pool you don't need.
Thanks for the reply Dave! I couldn't believe how quickly my new test kit arrived after ordering. Wonderful service! My only hiccup with the kit was the TA test which states "changes to red". I couldn't get "red", more like a hot pink. :) CYA is kind of tricky, but you get the hang of it after a test or two.

Yes, the solar cover remains on the pool 24/7 unless there are bodies swimming. Huge PITA with the constant on/off, but it really helps keep the pool warm as we are in NY.

Since all is well, I will probably go back to lurkdom.

Thanks again!



TFP Expert
LifeTime Supporter
Feb 23, 2008
Denton, TX
The TA test results as more of a hot pink, as you described it to be. No problem there as you are getting a correct result.