Use hole to match color according to instructions; but the cloth pad with the reagent covers the hole. Also, the color of the pad and the colors on the bottle don't match very well under 2700K light. When you place the hole over the bottle they don't really line up. It's bad enough that I couldn't find a match on the two strips. There is only ONE reagent spacer per strip. It is used to test both 1ppm and 10ppm. The difference is how long you soak the mat in the water. 5 seconds for 10ppm, 10 seconds for 1ppm. Then you wait 30 seconds for the reagent to take effect, you have 15 seconds to adjust the color - while the color changes fairly quickly. And given 2700k, nothing fits. Also, reagent pads change color as you watch them, which is to be expected, but they never stop changing color. You only have a few seconds to "read" the result, and if you miss the time slot, you'll lose the bar. And the color difference within the 15-second matching window is like chasing a rainbow. The really lousy part of the "design" is that if you need to match colors to fabric rather than reference colors, you can't use matching strips to match the colors. the test strip next to the flower line is too light. And when you touch the bottle with a strip, the strip wets the bottle and you only have part of a small hole of one color, with a ring of another color around it, and a third color outside where there is no hole. try again in daylight. The same thing. Can't find a color match - or anything closer than anywhere from less than nothing to halfway up the chart. Unsuitable for me. Send back the remaining strips as they seem defective to me. It seems to me that they use very subtle shading to differentiate between readings. Anyone with color blindness should avoid it. However, color variations when reading make them unsuitable for most.
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