PH Difference between K2006 & K1000

[giroup01]

Reagents are fresh (approx 6 months to 1 year from manufacture date)

[chem geek]

I heard back from Taylor Technologies who wrote the following:

I reviewed your concerns with the Production Manager and the Quality Control department, they both confirmed that the lot numbers you provided where made to our quality control specifications. I ran several pH tests using both the K-2006 and the K-1000 color comparators. I tested standard pH solutions 7.0,7.2,7.6,7.8 in both comparators using a fresh lot of R-0014 in the K-1000 comparator and a fresh lot of R-0004 in the K-2006 comparator.

I found that each standard measured exactly to the K-2006 color comparator. K-2006 ranges are ( 7.0,7.2,7.6,7.8). The K-1000 color comparator has different ranges ( 6.8,7.2,7.5,7.8,8.2). With the K-1000, I found the 7.0 standard solution measured between the 6.8 and 7.2. The 7.2 solution measured exactly at 7.2 .
The 7.6 standard solution measured between 7.5 and 7.8 on the comparator. The 7.8 standard solution measured exactly at the 7.8 on the color comparator. I viewed all tests under the same light source.

Since the ranges are different between the two color comparators there was some estimating with the K-1000 when testing the standard solutions. Keep in mind this test is a color comparison and it can be subjective when reading your results compared to another person running the same test.

As [name deleted] mentioned in the previous email, the difference in the reagents are minimized as long as they are used correctly (with the correct sample size, number of drops and the same light source).

Note that they did not test using pool water, but standard solutions. I don't know if that makes a difference (maybe chlorinated water affects bad reagents more?). If you want to pursue this, I suggest you contact Taylor directly and maybe you can get fresh reagents and send back the ones you have so they can reproduce the problem. You might also try measuring the same sample of dechlorinated water with the two kits.

I'll have Ben PM you with the technical support contact person info.