Total Chlorine a little higher then Free Chlorine

Brilis

Active member
May 4, 2020
40
Fair Lawn, NJ
Morning guys,
Did a water test last evening and my total chlorine is just a little higher then my free chlorine.

2.0 for free chlorine and maybe 2.3 for total chlorine.

Other #'s are follows;
PH 8.1
TA 130
CYA 40

Added Muriatic Acid last night according to pool math. Thoughts?

Thanks!!
 

DorsalSpine

Gold Supporter
Silver Supporter
Jul 8, 2013
678
Columbus, Ohio
Are you using the FAS-DPD test or a color block test? The FAS is more accurate and breaks chlorine down to free chlorine (FC) and combined chlorine (CC). FC is good, high CC is bad. High CC means your chlorine is having to combat algae in your water.
 

jimbethesda

Gold Supporter
Jul 2, 2018
439
Austin, TX
Are you using the FAS-DPD test or a color block test? The FAS is more accurate and breaks chlorine down to free chlorine (FC) and combined chlorine (CC). FC is good, high CC is bad. High CC means your chlorine is having to combat algae in your water.
+1 on this. With a value ending in .3, that suggests you aren’t. How are you getting your numbers?

If your numbers are accurate, a CC of .3 (TC-FC=CC) is not the issue. .3 is ok. The issue is your FC is too low. You need to follow this chart. With a CYA of 40, the absolute minimum for FC is 3 with a target of 5-7 (assuming no SWCG).

 

Brilis

Active member
May 4, 2020
40
Fair Lawn, NJ
Thanks. I am testing with a 2005 test kit, color block. I ordered the add on so I can test chlorine using DPD. Has not arrived yet. Ordered it right from Taylor over a week ago. So I am probably a little off. I added liquid chlorine this AM before I left for work according to pool math. Just wondering if I should be doing anything else. I will retest again tonight.
 

DorsalSpine

Gold Supporter
Silver Supporter
Jul 8, 2013
678
Columbus, Ohio
You look good. Test your PH again since you added acid just to make sure you ended up where you expected. Your FC is too low for a CYA of 40. You need to be in the 5 - 7 range. This is where you really need the FAS test. Your typical color block test isn't that accurate and the tendency is to hold your FC too low. You are skirting on the edge of an algae outbreak.
 

jimbethesda

Gold Supporter
Jul 2, 2018
439
Austin, TX
Thanks. I am testing with a 2005 test kit, color block. I ordered the add on so I can test chlorine using DPD. Has not arrived yet. Ordered it right from Taylor over a week ago. So I am probably a little off. I added liquid chlorine this AM before I left for work according to pool math. Just wondering if I should be doing anything else. I will retest again tonight.
Just make sure you don’t let your FC drop below the minimum again