Testing Comparisons - TF-100 vs. Color Q

[Patrickoleary]

HI there. Been in the forums reading for almost a year, but recently started posting.

I posted in another thread about my SWG FC. Through that conversation, I was encouraged to get a TF-100 test kit to ensure my calculations are accurate. I was previously using a LaMotte ColorQ 7.

This morning my TF-100 arrived. Because I was curious, I tested the water back to back with each test. The results are posted below. I assume everyone here goes by the TF-100, but just found the results very curious. If the TF-100 is indeed correct, which I have no reason to not believe it, the ColorQ is WAY off and has been. It is especially off with regard to FC and CH. I have been monitoring my pool all summer (my first summer) using the ColorQ, and haven't had many issues. The water has been crystal clear, but since switching to a SWG I have found my FC cannot keep up. Which led to the other discussion, which led to here.

Any thoughts or comments on the two tests. I will continue to use the TF-100, but wanted to post the results.

EDIT: My CYA on the ColorQ for the last month (tested 3x) was 68 every time. My local pool store was 68. TF-100 was 70. Today, ColorQ was 95. No idea why. But, I am started to see why I am always messing with chemicals, because the ColorQ is off.

EDIT 2: My markup on the image didn't come through. The top test is TF-100. The bottom is ColorQ.

 

[Msch99]

Thanks for sharing!
My only testing experience has been test strips and TF100, so a no brainer here!?

 

[Patrickoleary]

Thanks for sharing!
My only testing experience has been test strips and TF100, so a no brainer here!?

When we bought the house and I researched pool testing, I assumed a digital readout and color chromatic test would be more accurate.

The TF-100 sort of reminds me of all those chemistry labs I absolutely hated with a passion in college, except this is fun.

 

[Jimrahbe]

Pat,

I also have the FT-100 and the ColorQ and I find that my results are always very close except the CH.. This is because the ColorQ tests for Total Hardness and not Calcium Hardness (They call it CH, but it is actually TH..) I use my TF-100 and measure the CH and then use that number to adjust the ColorQ's reading.. As an example, if the the actual CH is 300 and the ColorQ says 400, I know to just subtract 100 from the ColorQ's reading..

So, you might ask why I use the ColorQ at all... I take care of three pools and find the ColorQ compact and easy to carry and use..

I use my TF-100 like a torque wrench.. When I want to tighten a nut to some very specific number, I use the TF-100, if I just want to know that the nut is tight, I use the ColorQ. It is too bad we can't combine the two..

Thanks,

Jim R.

 

[Patrickoleary]

Pat,

I also have the FT-100 and the ColorQ and I find that my results are always very close except the CH.. This is because the ColorQ tests for Total Hardness and not Calcium Hardness (They call it CH, but it is actually TH..) I use my TF-100 and measure the CH and then use that number to adjust the ColorQ's reading.. As an example, if the the actual CH is 300 and the ColorQ says 400, I know to just subtract 100 from the ColorQ's reading..

So, you might ask why I use the ColorQ at all... I take care of three pools and find the ColorQ compact and easy to carry and use..

I use my TF-100 like a torque wrench.. When I want to tighten a nut to some very specific number, I use the TF-100, if I just want to know that the nut is tight, I use the ColorQ. It is too bad we can't combine the two..

Thanks,

Jim R.

Great insight. I agree with you on the ColorQ ease of use. Fill the vial, blank it, 5 drops, test, next vial, repeat. Extremely quick and easy.

In my testing though, my ColorQ is always too low. Your method wouldn't work for me. So in this case it read 95 vs. 275 for the TF-100. My pool store said it was 255.

 

[Salt_Water_Sam]

Check the expiration for your CH2 vial. It has a very short shelf life. Like 6 months or less (expired can give false low readings). I use a ColorQ as well but also have the Taylor K-1515 test kit for SLAMMING purposes (K-1515 is the FAS-DPD chlorine test that is in both the TF100 and K-2006 test kits). If I am reading your screen shot correctly, the FC readings are also lower on your ColorQ than the TF100. I have experienced similar results when I compare FC and TC against the K-1515. This makes me also want to get a TF100 just for comparisons! I do like Jim's analogy on the two and would probably use them both in similar fashion.

 

[Patrickoleary]

Check the expiration for your CH2 vial. It has a very short shelf life. Like 6 months or less (expired can give false low readings). I use a ColorQ as well but also have the Taylor K-1515 test kit for SLAMMING purposes (K-1515 is the FAS-DPD chlorine test that is in both the TF100 and K-2006 test kits). If I am reading your screen shot correctly, the FC readings are also lower on your ColorQ than the TF100. I have experienced similar results when I compare FC and TC against the K-1515. This makes me also want to get a TF100 just for comparisons! I do like Jim's analogy on the two and would probably use them both in similar fashion.

Yes, the FC is also lower on the ColorQ.

The ColorQ vials were all purchased in April I would think they aren't expired yet, but I don't recall where I bought it online. It very well could be.

 

[Salt_Water_Sam]

Yes, the FC is also lower on the ColorQ.

The ColorQ vials were all purchased in April I would think they aren't expired yet, but I don't recall where I bought it online. It very well could be.

The expiration date should be printed on each individual bottle (FC, TC, PH, etc) Mine have varied considerably but the CH2 is always very short.

 

[Jimrahbe]

It may be because I don't try to get the pink to turn crystal clear.. I just add drops until the pink goes away.. I suspect that our tests are a few drops apart...

I also use the speed-stir... as I can't count and swirl at the same time..

For me, it makes little difference, as I never get anywhere near my minimum FC level...

Jim R.