What is the nitrite concentration of your mature reef? And why it may matter.

[Randy Holmes-Farley]

What nitrite concentration is enough to be of concern when testing nitrate

Depends very much on the test kit.

 

[taricha]

What nitrite concentration is enough to be of concern when testing nitrate

Depends very much on the test kit.

To just take the measurements Dan and I did to logical conclusions....
Hanna LR NO3, at 0.2ppm NO2, you are adding maybe 0.3 to 0.5ppm NO3 to the reading. At that point you are outside Hanna's stated error, and I wouldn't rely on it above that without a correction.

Red Sea NO3 pro: at 0.2ppm NO2 you are adding maybe 1 to 2ppm NO3 to the reading. If you are just quantifying by color cards, this is probably OK, but I wouldn't go higher (without correction).

Hanna HR NO3: at 0.5ppm NO2, you are adding around 2.5 to 5ppm NO3 to the reading. That gets you outside Hanna's stated error. And probably higher than you want to go without a correction.

neither @Dan_P nor I have messed with quantifying NO2 interference on the NO3 kits that seem to give stuff like 100ppm NO3 from < 2 ppm of ammonia during cycling. They would be expected to be much worse and it's possible low NO3 measurements aren't practical at even 0.10ppm NO2 or below.

 

[Lasse]

Hanna LR NO3, at 0.2ppm NO2, you are adding maybe 0.3 to 0.5ppm NO3 to the reading. At that point you are outside Hanna's stated error, and I wouldn't rely on it above that without a correction.

In line with the result I got when I analyse a standard with 1 ppm NO2

Hanna HR NO3: at 0.5ppm NO2, you are adding around 2.5 to 5ppm NO3 to the reading. That gets you outside Hanna's stated error. And probably higher than you want to go without a correction.

The same

Sincerely Lasse -