I hear ya Greg. I'm more stuck on the cost of the K-Strong or whatever. I imagine a bottle will last forever though so once bought it should be OK.
My most recent frustration with test kits involve Magnesium though. I started getting really frustrated that no matter how much Mg supplement I was adding to my makeup water, it would only go up a tiny tiny little bit. 900. Dump Mg. 905. Dump a whole lot of Mg. 910. Go buy more Mg. Dump it in. 905. "What the ...". So I went and bought an Elos test kit (I was using Salifert). 1300. 1300! That's quite a discrepancy. I've never gotten bad readings before from Salifert though so now I'm sort of stuck on who do I believe, $30 per each test kit and such wildly different results between the two.
I think I can produce a rant about just about any test kit or electronic tester that I've ever used to test any parameter. I didn't think I was "one of THOSE people" but maybe I am. You know the type. Usually it's a parent or an inlaw where you're like "For the love of GOD please don't touch my computer!! ... Or my stereo. ... Or.. um .. my TV. Or my phone." (because everytime they do it takes you weeks to get it fixed back up to where you had it before). Other people can come along and press every button and things are fine, but these folks touch one button and poof, virus, or poof, all your emails are gone ... (and all they touched was your phone .. how on earth did you DO that?? "I dunno I just pressed on, I swear!"). I seem to be that person with test kits.