Hi out there. I love this site. After a few years at the mercy of my pool guys, I feel like I'm finally in control.
I thought I'd try to add to the discussion by talking about the AquaCheck TruTest. It's a meter that reads its own special test strips, and claims +/- .1 accuracy on Chlorine (total CL, I think), +/- .1 accuracy on pH, and I think +/- 10 on TA. I paid $42 for it at Amazon. It comes with 25 test strips -- I paid another $8 for 50 more. My meter says version 2.2.
I like the idea, because I'm never sure how well I do the color matching in the K1000. It seems a much better alternative than a pH meter, which is apparently a pain to maintain, and overkill for a single pool.
The gripe about the TruTest on the net is that it does not deliver consistent accurate results. I've found that if you don't consistently follow the directions, especially about cleaning and drying the slot, not shaking the strip after dipping, not sliding the strip along the glass and blocking strong ambient light, you will indeed get readings all over the place. For my test, I went poolside, dipped consistently and used a shoebox to block ambient light after inserting the strip. I wiped the slot dry between attempts. Here are the results:
Trial CL pH TA
#1 7.3 8.0 110
#2 7.4 8.2 110
#3 7.6 8.0 090
#4 7.8 8.1 100
For yuks, I tried one where I slid the strip along the glass while inserting, something the directions tell you not to do:
#5 8.6 8.2 130
Using the K1000 I got CL 3-6, pH 8.1 (slightly lighter than the 8.2 reference). Using the TFT100, I got FC 7.5 CC 0.0 TA 110.
So, I conclude that when used carefully, the TruTest is easy to use and reasonably accurate. I would recommend it to people who have trouble matching colors or qualms about the disposal of the carcinogenic FC testing reagant Orthotolidine. (My pool guy dumps it back in the pool, which pisses me off.)
I think most of the problems people have with the TruTest are due to ambient light. The directions say to use the blocker in strong sunlight. It's a black piece of cardboard a bit bigger than a credit card that you can put over the slot while it's working. I don't think the warning is strong enough. I think the meter works best if you try to get it in near darkness. Like I said, I cover it with a shoebox after inserting the strip, which works fine.
I've been using it about a week now. I went back it my pool log to pull the two places where I used the TruTest and also did a K1000 or TFT100 test to compare:
Date K1000 TFT100 TruTest
7/29 CL 5-10 pH >8.2 FC 10 CC .5 TA 100 CYA 60 CH 260 CL 9.4 pH 8.4 TA 130
8/1 CL 3-6 pH 7.5-7.8 FC 4.5 CC .5 TA 90 CL 4.9 pH 7.6 TA 120
Hope this is useful to people out there. Thanks for the great site.