Which test is giving me the accurate FC reading?

[MT]

This is my second season using the Taylor TF-100 kit + K-1000, so I'm pretty comfortable using it. The start of this season I got a full refill of everything, so all regents are brand new. I also had a pool store test the water, and I have two different brands of test strips that are also brand new. Here is what I am getting:

K-1000 FC = 4
Chlorine drop test FC = 3.5
Pool store FC = 0.75
LaMotte test strips FC = 1
Taylor test strips FC = 1

How do I know which is correct?

 

[Bama Rambler]

FAS-DPD no question!

 

[ping]

There is a reason why the TF-100 is a recommended test kit and that is due to the FAS/DPD test. It is the most accurate of all those tests, and it measures FC up to 50ppm.

The K-1000 is so so up to 5ppm, but even that is more of do I have FC or not.

Pool store and test strips I'll put in the same category, you never know if it is right or wrong and most of the time it will be wrong.

 

[JVTrain]

The TF-100 FAS/DPD test is the accurate number. The K-1000 is only as accurate as your eye is able to interpret. In this case, you now know what 3.5 should look like on your K-1000. Pool store/test strips are different than the other two by a measureable/significant amount. Now you know why we recommend proper test kits.

 

[Donldson]

My favorite part of your test is how the test strips and pool store are all close... and all way wrong. This is why when someone new comes to the site and gives us test strip results "confirmed by the pool store" or vice versa we still can't accept that as accurate. There are no tests on the residential market that rivals the accuracy of the FAS-DPD test.

As for the OTO test in the k-1000, it tests free chlorine. So between the possibility of misreading the color and the possibility that you have up to 0.5 CC then I would say it gave you a pretty good confirmation of your FAS-DPD results.

 

[Patrick_B]

FAS-DPD no question!

Always.....