I was confused about comparing the tube to the color chart. When you look at it, if you put the tube directly on top of the white chart, it's darker than if you hover it 1/2 in above the chart. Which will give an accurate result? I ask because when I put the tube on the white, it's 1.0 and when it's hovering over, it's 0.5, or maybe I'm just stupid?

YOu are not stupid at all! That is an extremely good question. I think the tests are designed such that you place the tube up against the white of the card. But remember - the color reading is only as good as your eye's ability to deterimine the differences in the color. REadings have a + or - that is quite large - which is why it only says "!" or ".5" and not ".7". If you have between .5 and 1 ppm ammonia showing, you know that you have "some" - but not outrageous amounts.

The drop tests are more accurate than the dip strip tests in most cases - the color differences are slightly easier to differentiate . But they still have a built in degree of inaccuracy.

Oh, I'm great at distinguishing colors, I'm really picky when it comes to stuff like that, I criticize my friends when they're off... but it doesn't say on the directions if you hold it against it or over it, so I'm glad you cleared that up for me. Thanks!

So it only shows you a range? So if it's in between 2 colors, that's how much there is? I see now. It basically tells you "too much" or "just right".

I know with my test kit it says to put the tester on the white part of the reading card, and hold it up to a bright light to read accuratly. Its not a stupid question at all!!!! I know with me, they look two different colors when you hold it up to the white, and then hold it away from the white.

Yeah, that's why I got confused. Glad to know I'm not the only one....

The glass from the tube messes with the color of the liquid in the tube. I don't like holding it right next to the card as I have yet to see a result that exactly matches anything (even when a reading is zero for certain, like testing tap water for nitrites, it doesn't match the color on the card).

I have been setting the card on my white bathroom counter, standing the tube up behind it, taking a step away, and judging it that way. When I do that, I get good lighting from all angles of the tube and the colors appear truer to me. When I do that, the colors in the tube from a zero level test match the 0 ppm color on the card. That makes me think that holding it right up against the card will give a false reading.

Try it that way. I do ammonia, nitrite, and nitrate, set all three cards down, stand up all three tubes, and step back. The colors are much easier to match up that way.

Ok, I'll try it.