Nitrite Tests - Weird Results

[mound]

Hi - I'm in the process of finishing up a fishless cycle..

normally on established tanks, when I do my nitrite tests (the test tube/color kind) I drop the 5drops of reagent into the test tube, and it turns a sky blue immediately (the 0ppm reading), and stays that way (you're supposed to wait 5 minutes before reading the result.)

The tests I'm doing now at the end of my fishless cycle - when I first drop the reagent into the test tube, it immediately turns purple (a high reading) but within the 5 minutes turns to sky-blue (the 0ppm reading)

I'm just curious why this is? Could it be because the Nitrates are extremely high at this point? (I haven't done the end of cycle water change yet and so Nitrate has go to be upwards of 400ppm)

Just curious

[loganj]

Sounds like you're using the Aquarium Pharmaceuticals kit. Never had one do that before. It's possible I guess, that the nitrate levels could affect the color of the reagent at first. I don't think you'll have nitrates anywhere near 400 though (typo?)...maybe in the 40-60 range. I have used the same nitrite kit on an aquarium that had nitrates in the 160+ range and didn't get any unusual results. How old is your kit? I'd try a different test kit before I did anything else.

[mound]

well again, the fishless cycle had been going on for 14 days, with no water changes, all that Nitrite being converted into Nitrate - no dilution, reading is the 100 & above value - couldn't it be 400 or so? just guessing.. (yes, Aquarium Pharmaceuticals kit.)

My fish arrive from armkes.com soon - I did a 60% water change.. Nitrates now reading about 20ppm.. same thing with the Nitrite test, turns purple first, 5 minutes later, it's the sky blue (0ppm) reading.. I do the same Nitrite test in my other long established 55g tank, the test immediately turns and stays the 0ppm color..

I wonder if I should do another big water change before putting the fish in