Quote Originally Posted by CarlD
"Really Orange" is not a measurement.
Actually, it is.

There's just not a color chart for it. But, now that I've got a color laser printer (just purchased to make the new PS234 bottle labels), I'm looking into making a high range scale for the PS200, that I can put on the inside label.

Very roughly, though:

really dark yellow (darker than the darkest on the PS200) => 5 - 15 ppm
light orange => 10 - 20 ppm
dark orange => 15 - 30 ppm
brown => 30+ ppm

I've got to run tests to actually define that better; the colors above are just 'seat of the pants' guesses, based on prior experience.

Ben