stupid question about water testing results

[sansouci01]

when I check the color of my test water, I use a sheet of white paper instead of holding it against the color chart paper. My question is, do you hold it right up against the paper or a little bit off the paper. big difference in the color from one method to the other. my nitrates read 20ppm when I hold it close to the paper. right up against the paper it reads 50ppm ( color looks darker )

 

[fort384]

I would read it up against the paper. Titration tests are subjective no matter how you slice it, unfortunately.

 

[Skunky]

I don't lay mine down on the paper because there is a kind of shadow effect, depending on how the light hits it. If the light goes right through it, then it works better. Does this make sense? Play around with the tubes in different lighting situations to figure out whether or not it is being shadowed.

 

[Bbarb27]

I don't lay mine down on the paper because there is a kind of shadow effect, depending on how the light hits it. If the light goes right through it, then it works better. Does this make sense? Play around with the tubes in different lighting situations to figure out whether or not it is being shadowed.

I agree with this. I try to hold mine up to the white part of the paper but far enough away that light shines through it. I also try to use natural light (by a window) to read the colors.

 

[Skunky]

I agree with this. I try to hold mine up to the white part of the paper but far enough away that light shines through it. I also try to use natural light (by a window) to read the colors.

Yes, I think you described it better than I did. Thanks!