Observations and questions on the TF-100 test kit

[Chas]

I received my new TF-100 test kit last week. Pretty nice kit! Of course I had to go play with it as soon as it arrived. I especially like the nice crisp colors on the handy small test kit for CL and pH. The colors are so much brighter and easier to see than in my aged Rainbow 78HR kits that have been my standard kits since I can remember. It’s also helpful that the volumes of water for each test in the small kit are the same so one fill, 5 drops in each tube, one cover and one shake to see both tests. The 78HR uses different volumes and is more cumbersome.

The time honored 78HR “5 bottle kit” tests for CL (and free CL with experience reading it), pH, acid demand and TA.
So, comparing the 78HR kit with the TF-100 I make a few observations and have a few questions:

1. To test for pH the 78HR instructions say: “2. Add one drop solution #4 (2 drops if chlorine test is above 1.5ppm)….” “3. Add 5 drops solution #2 and…..compare to pH color standards.”
   The solution #4 bottle is labeled “Chlorine neutralizer”. The TF-100 2 bottle daily test kit says nothing about a chlorine neutralizer. When I compare the readings between the TF-100 and the 78HR, the TF-100 seems to read a bit higher pH than the 78HR. Maybe it’s the color standards on my 78HR are faded, or the reagent is slightly different, but the colors in the test vial water are indeed slightly different with the TF-100 being a tad darker, or higher pH shade.
2. To test for total alkalinity the 78HR instructions call for the same procedure with the “chlorine neutralizer”. The TF-100 calls for 2 drops R-0007, then 5 drops R-0008 before beginning the titration steps. Is R-0007 a “chlorine neutralizer”? If so, why isn’t it used in the pH test? Would the level of CL in the water affect the TA test with the TL-100? Unfortunately, I ran out of my solution #3 (acid demand and TA titration) or I would compare these tests between kits.

Thanks for putting together such a capable test kit! I’ll enjoy using it for years to come.

 

[Casey]

Chlorine will affect the pH test and give false high readings if the FC is over 10ppm. It is suggest that you do not adjust pH if you are running an FC at SLAM levels due to high FC. On the other hand, I don't think high FC affects the TA portion of the test. If you were to chose which test to believe, go with the TF100.

Other's will touch on anything I skipped over. Welcome. Enjoy your stay.

 

[tim5055]

While I would love to make myself look good, I know,chem geek always has an answer. Here is his answer to a previous similar question

There is a chlorine neutralizer already in the Taylor (and TF-100) kits for the TA test. The R-0007 reagent is sodium thiosulfate which is a chlorine neutralizer. This is done to neutralize the chlorine for the TA test. However, such neutralizer solutions are themselves high in pH and the reactions with chlorine are inconsistent in their effects on pH (depending on factors such as the TA level). So while you can add some R-0007 before adding the pH reagent, you may still get a "too high" reading, though at least you won't get the bleached-out half-indicator result of purple. You can certainly add a couple of drops of R-0007 to see what it does -- just don't trust the final result.

The Taylor R-0004 pH Indicator solution has a proprietary combination of chlorine neutralizers already in it that try and keep the pH the same when chlorine gets neutralized, but there's only enough to neutralize roughly 10 ppm FC or so of chlorine. They didn't want to add more since they didn't want to adversely affect results by this neutralizer solution (i.e. too much could affect the pH). Handling 0-10 ppm FC seemed reasonable.