I have both the Lamotte ColorQ Pro 7 and the TF100 test kits. I really like the Lamotte from an ease of use perspective and have only recently been testing with the TF100. Over the past few days, I have been using both testers to compare the results since I installed a Stenner Pump system and am checking the water a few times a day anyway.
Here are my last 4 days test results:
Day 1:
Lamotte - FCL=5.88, TCL=5.96, PH=7.4, TA=76, CH=222, CYA=59
TF-100 - FCL=8.0, TCL=8.0, PH=7.5, TA=90, CH=375, CYA=45
Day 2:
Lamotte - FCL=6.36, TCL=6.47, PH=7.3, TA=69, CH=221, CYA=63
TF-100 - FCL=9.5, TCL=9.5, PH=7.4, TA=90, CH=350, CYA=45
Day 3:
Lamotte - FCL=6.65, TCL=6.79, PH=7.5, TA=66, CH=216, CYA=58
TF-100 - FCL=10.0, TCL=10.0, PH=7.7, TA=80, CH=350, CYA=40
Day 4:
Lamotte - FCL=6.81, TCL=6.81, PH=7.3, TA=59, CH=221, CYA=62
TF-100 - FCL=9.0, TCL=9.0, PH=7.4, TA=70, CH=325, CYA=40
You can see that the Lamotte is reading consistently lower than the TF-100 for Chlorine, TA and CH and consistently higher on CYA. Based on all that I have read on this forum, the Lamotte is not as accurate (as far as correctness in reading) than what the TF-100 gives due to the testing method. Once my chlorine level comes down a bit, the two testers may come more in line with each other, but I'm leaning towards believing the TF-100 over the Lamotte results. I find the Lamotte useful in that the testing is super quick and since I know that is reads higher or lower on some tests, I can still use it as a quick and dirty way to detect upward or downward drift in the various levels and use the TF-100 when I need actionable results.