Testing puzzle

[CarolD]

I am a bit puzzled by my latest test results. I have two test kits. My main kit is a Taylor K-2006. I have a secondary kit (my first kit purchase, while I was still making the transition from test strips to drops) which is a K-1001. Both are less than a year old. I rarely use the K-1001 for anything other than a secondary color check on my PH test. The scale on the K-2006 doesn't include a 7.5 color, which I like to be able to see, especially since I am trying to keep PH a little lower than recommended here due to some scaling issues. Anyway, recently I was having a hard time guessing the color on my PH test, so I broke out the K-1001 and decided to test my PH with that kit. The color difference was dramatic. Like I was reading 8.2 (very pinky-purple) on the K-1001 vs. something in the mid 7s (orangey-red) on the K-2006.

I tried measuring the PH of my tap water, which has been run through a water softener. Both kits read about 7.4 on the tap water, and the color was IDENTICAL. I am baffled. Why would I be getting such a dramatic difference in color on my pool water, but identical readings on my tap water? My chlorine level when performing this test was about 6.5. Actually, here is a listing of my latest results.
FC 6.5
CC 0.5
PH 7.8???? who knows???
TA 80
CH 360 (hoping for some heavy rain or a lot of splash out to bring this down a little bit so my CSI gets below 0.0)
CYA 50
CSI 0.28
TEMP 91
I store my reagents carefully in an air conditioned house and out of the sunlight. They are about 9 months old. Of course, who knows how long they sat on a shelf before they were delivered to me?

Thoughts?

 

[frogabog]

Retest. The tap water result shows you that the reagents are most likely good. The wide range between kits indicates a possible testing error.

Another test from the same sample should also be the same. pH is not one that usually goes bad very fast.

Are you using R-0004 with the K-1001 test block? And which reagent from the K-2006?

 

[CarolD]

I tested three times! With the test block from the K-2006 I used reagent R-0004. With the test block from K-1001, I used R-0014. Weird, right? I am going to test both again tonight and post pictures shortly.

 

[CarolD]

Ok just finished testing for tonight. There is still a difference between the two test blocks, however, it is not as dramatic as previous tries. Last night, I dosed with MA to bring down TA and PH in the hopes of turning my 0.0+ CSI to less than 0.0. I was successful. Here are my test results:
FC 6
CC 0
PH 7.4 on my k-2006 test block
7.7 ish? on my k-1001 test block
TA 60
CH 350
CYA 50
CSI -0.26
TEMP 92

Here are the pics of the two different test blocks.
K-2006 K-1001

As I said, not so dramatic a difference, but clearly the K-1001 is reading higher than the K-2006. For tonight, I am trusting the 7.4 reading, since that is the target I was aiming for last night when I added MA.

 

[frogabog]

I don't have your eyes, but I see the K-2006 at 7.5 and the K-1001 at 7.6.

The K-2006 is not 7.4, it's looks to me to be a deeper orange, and the 1001 isn't red enough to be 7.7.

Regardless, the 2006 block is easier to read at .2 gradients, so I'd say go with that one. .3 gradients is a lot harder to interpret.

 

[CarolD]

Thanks, frogabog. The pictures really didn't illustrate the colors as well as I'd hoped they would. Or maybe, my eyes deceive me and the picture is a truer representation of the color! Regardless, your advice about going with the .2 gradients is good. That's what I'll do!