Readings using TF-100 odd?

mevrowka

Member
Aug 8, 2021
7
East Tennessee
I just got a TF-100 test kits so started testing. Total noob here but I can follow directions. I thought Total Chlorine was always greater than Free Chlorine but that's not what Im getting on my tests. I've done the Free Chlorine test 3 times and the Total Chlorine test 2 times, checking to be sure I used the right regeants and directions each time (plus I watched the videos).

Free Chlorine - 5
CH - 250
TA - 130
CYA - Something less than 20 since I could fill the tube completely and still easily see the black dot
Total Chlorine - .5
Ph - 7.8

So, do these results make sense? I thought Total Chlorine was supposed to be higher than Free Chlorine. Thanks!
 

mevrowka

Member
Aug 8, 2021
7
East Tennessee
Im really confused now.

The test kit has weekly instructions for a Chlorine Drop Test, where it states:
a. You will fill the cylinder with water
b. You add a scoop of R-0870
c. Add R-0871 till the solution is clear. This is where the instructions state "Count each drop until the solution turns back to completely clear. Multiply the number of drops you added x 0.5. Record this as Free Chlorine (FC)."

So that's why I thought my FC was 5. Those same instructions have a step 4 which tests for CC by adding 5 drops of R-0003. And finally, it tells you that adding FC to CC will equal TC.

In that kit, there is a little blue box (kit K-1000 which came with the T-100) with instructions stating it's testing for Total Chlorine/Total Bromine using R-0600. There are actually two tests, the other one is a Ph test using regent R-0014.

So is the K-1000 kit really testing for CC and not for TC? The K-1000 kit had instructions in the box that have a number on them (Instr #5113) so maybe I got the wrong instructions? Would pictures of the instructions Im looking at be helpful?
 

Kevinr14

Silver Supporter
Mar 8, 2021
296
Chandler, AZ
Pool Size
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Im really confused now.

The test kit has weekly instructions for a Chlorine Drop Test, where it states:
a. You will fill the cylinder with water
b. You add a scoop of R-0870
c. Add R-0871 till the solution is clear. This is where the instructions state "Count each drop until the solution turns back to completely clear. Multiply the number of drops you added x 0.5. Record this as Free Chlorine (FC)."

So that's why I thought my FC was 5. Those same instructions have a step 4 which tests for CC by adding 5 drops of R-0003. And finally, it tells you that adding FC to CC will equal TC.

In that kit, there is a little blue box (kit K-1000 which came with the T-100) with instructions stating it's testing for Total Chlorine/Total Bromine using R-0600. There are actually two tests, the other one is a Ph test using regent R-0014.

So is the K-1000 kit really testing for CC and not for TC? The K-1000 kit had instructions in the box that have a number on them (Instr #5113) so maybe I got the wrong instructions? Would pictures of the instructions Im looking at be helpful?


The fas/dpd test which are the instructions you posted test free chlorine and combined chlorine and your understanding of that seems to be correct. In addition, the k1000 is an OTO chlorine test which measures total chlorine and is not generally used as often other than to see if you have any chlorine since it's not as accurate and it has limitations.
 

mevrowka

Member
Aug 8, 2021
7
East Tennessee
The fas/dpd test which are the instructions you posted test free chlorine and combined chlorine and your understanding of that seems to be correct. In addition, the k1000 is an OTO chlorine test which measures total chlorine and is not generally used as often other than to see if you have any chlorine since it's not as accurate and it has limitations.
OK, I think I understand now. Based on that explanation, it seems I should just ignore the TC test from the K1000 since it seems very inaccurate. If I only had the OTO chlorine test available to me, I'd have assumed I had little to no FC given the TC was only 0.5 - and thats not the case.

Thank you. I appreciate the help!
 

YippeeSkippy

Mod Squad
Gold Supporter
LifeTime Supporter
Jan 17, 2012
17,725
Evans, Georgia
We only expect you to use the FAS-DPD (powder test) for an exact FC and Combined Chloramines (CC) reading. Use the block in the blue box (K-1000) just for your pH checks.

Some will do a fast test with the block in the K-1000 kit just to tell them "Yes I have chlorine" or "Nope..no chlorine" when the exact amount isn't necessarily needed.

We don't care about TC as we are interested in the exact numbers for FC and CC. Telling someone what the TC is is worthless as how much of that number is the FC or CC??

Maddie :flower:
 
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