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-   -   help with reading API test-Nitrites (http://www.tropicalfishkeeping.com/beginner-freshwater-aquarium/help-reading-api-test-nitrites-67725/)

GwenInNM 04-11-2011 04:52 PM

help with reading API test-Nitrites
 

The results of my nitrite test do not show the "sky blue" that indicates no nitrates, but it has no purple in it either. Is the blue on the card a bit off from the liquid, because I don't know how to read this. I'm hoping I have no nitrites, but the blue color is a bit different than the card color.

Any ideas?

Gwen

Byron 04-11-2011 04:59 PM

Gwen, make sure you hold the tube against the card, and view it in daylight if possible. Artificial lights often distort various colours according to their spectrum/kelvin.

As long as the tube water is ot darker than the card for zero, you're OK.

GwenInNM 04-11-2011 05:11 PM

Quote:

Originally Posted by Byron (Post 645594)
Gwen, make sure you hold the tube against the card, and view it in daylight if possible. Artificial lights often distort various colours according to their spectrum/kelvin.

As long as the tube water is ot darker than the card for zero, you're OK.

I did hold it up to natural light, and ran the test twice. I guess since it is darker than the card, I still have a trace of nitrites, but not up to .025 - almost there!!

Thanks

Byron 04-11-2011 05:21 PM

Quote:

Originally Posted by GwenInNM (Post 645604)
I did hold it up to natural light, and ran the test twice. I guess since it is darker than the card, I still have a trace of nitrites, but not up to .025 - almost there!!

Thanks

Could be. I've forgotten from the last time i did a nitrite test, was years ago... You were careful about the number of drops? I have had an additional drop slip out in pH tests, and of course that makes the test useless. You also need to hold the regent bottle vertical so the drop is the right size. Pardon me if this is all known...but it can vary the results a lot.

whitecloud34 04-12-2011 10:44 PM

Actually I always have this problem but I always figured it was just the lighting. I have a hard time matching pH even and a lot of times it looks like a color somewhere in between what's on the card. Nitrite readings for me are always differnt looking from the 0 color on the card but I figure as long as there's no trace of purple in it then it must match the 0. Sometimes what I do--and I don't know if you're even supposed to do this--but I lay the card down flat on a table and stand the tube up and look at it at eye level and somehow the colors match up easier. Again, not sure if you're supposed to do this "quirk" due to possible inaccuracy so I'm not recommending it lol but that's what I do a lot.


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