TF-100 CC and TC question! Help!!


Bronze Supporter
Dec 24, 2018
Columbus, OH
Ok so I’m using the TF-100 kit as well as my PoolMath app and following the instructions EXACTLY as the kit says. For CC after the 3rd drop and a good swirl, the water was completely clear. I ran to the bathroom for no longer than 2 mins, come back and it’s a light pink again like when I first tested it (and yes, I swirled it well). What the heck?! Now what do I do? Keep dropping R-0871 until it goes back to clear? My FC reading is 1.5 but CC is driving me insane. It turned totally clear after the initial 3 drops! Is this the number I should go based off of since instructions don’t say to wait a couple minutes?

2nd question (but slightly less important at the moment), when adding and getting the TC, what do I put in the PoolMath app? It doesn’t have a TC record part, only FC. I swear I’m losing my mind lol. Helppppp!! My annoying mother-in-law wants to come swim and day drink with me so I gotta get this water balanced. Thanks in advance!



Active member
Aug 1, 2019
SW British Columbia
CC is not the same as TC? Yes, I did do the Pool School.
I've been trying to care for our pool for 34 years, testing only the pH and free chlorine. DIdn't know any better. On occasion (like at pool opening + when I have trouble) I take a sample to the pool shop where they do more thorough testing, and sell me more chemicals. I have never tested for CYA. The methods proposed here on TFP are a total paradigm shift for me.
This year I switched to 5-part test strips (Poolmaster Smart Test™) which showed promise, but often seem to show results completely different from what the pool shop reports. Okay, the strips were a bad choice.
I guess I need to move to a new system. But in 2 weeks we're leaving on vacation, and the pool will be in the hands of our house-sitters, who will have a complicated sheet of instructions compiled by yours truly. Next year will start over.


Gold Supporter
TFP Guide
Jun 8, 2019
Milwaukee, WI
FC = free chlorine, the amount of chlorine that hasn't been used yet to sanitize the pool.
CC = combined chlorine. FC becomes CC when it sanitizes something. Under normal conditions, the CC is then broken down by UV light and the remaining FC in the pool, so it should be under 1ppm.

TC = FC + CC. If you know FC and CC then you can just add them together to get TC. TC doesn't mean much because FC is what really matters (along with making sure CC isn't too high, because if it is, then the FC is rapidly working on something and you shouldn't have that much for the FC to work on that CC builds up). Some tests only test TC, though, so you see the term still.
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Bronze Supporter
Dec 24, 2018
Columbus, OH
With the TF-100 Kit, the little basic container and drops for Chlorine/Bromine and pH, is this an idea of the TC or FC? I know these numbers are for reassurance only and not to be recorded in the pool math app, but it’s been bugging me lol