Adding chlorine but FC still off


Bronze Supporter
Nov 3, 2019
Marietta, GA
So I’m adding HDX (20 059 date) liquid chlorine but fc numbers don’t seem to reflect my addition. It’s reading low. I thought maybe my liquid chlorine was low even though only a month old. But then I tested 18gal tap water in the bathtub with 5ml chlorine added and fc went from 1 to 10 (expected 7.3 jump) so I think it’s fine. Any ideas? My estimated pool volume could be off but when adding muriatic acid the numbers seem to be right on.

Can you guys see my Pool math logs? If not how do I link it?


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Your PM log is not being shared. To enable sharing tap the hamburger menu n the upper right and scroll down towards the bottom to Sharing and turn it on.

Just add more LC in small doses until you get your desired FC level. See how much it takes.
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