So, perhaps a few of you will find this interesting. It's been frustrating the heck out of me.
First, today's test for FC and pH:
To my eye, this looks like FC = 3 and pH = 7.0'ish.
I loaded the image above into the computer, picked the colors, and did a full 4th order multivariate match by HSV... a bunch of engineering speak for letting the computer pick the match on Hue, Saturation, and Value of each color. The computer puts the values at FC = 5.3 and pH = 7.5. That can't be right, my eye tells me.
So, then I match (4th order) by Hue alone, and I get numbers that don't seem so terribly off, but still not quite right: FC = 2.0 and pH = 7.2.
Then I do the same with my
test strips, because they test many more parameters (namely CYA), and I get the following, by full 4th order HSV multivariate match:
TH ppm 190
FC ppm 3.4
TC ppm 6.3
CYA ppm 90
TA ppm 135.9
pH ppm 8
Here's some pictures of the test strip against the bottle:
My eye has more trouble picking test strip colors, but here's the two things I'm primarily comparing:
FC
- FC
- K-1004 kit
- 3 by eye
- 2.0 by computer (by Hue only)
- 5.3 by computer (by HSV)
- Test strip
- 3+ by eye
- 3.4 by computer (by HSV)
- pH
- K1004 kit
- 7.0 by eye? Really doesn't look like any of the samples, to me.
- 7.2 by computer (by Hue only)
- 7.5 by computer (by HSV)
- Test Strip
- 7.8 by eye? Really doesn't look like any of the samples, to me.
- 8.0 by computer (by HSV)
It looks like the computer does a decent job of reading test strips, but terrible with the Taylor (K-1004) kit. Perhaps that's why my local store uses a computer to analyze test strips, as their primary method.
Here's why it's important: Going by eye on the Taylor kit, I've been adding pH Up, over and over. It still looks low to me, but the test strip says its high. Computer analysis of the Taylor kit image shows it's somewhere in the middle.