Weird Nitrate Measurements

[VR28man]

So, last night when I was measuring nitrate with the salifert kit, I followed the instructions and after the time mandated by the instructions (IIRC 3 minutes) my nitrate was reading 2.5ppm.

I left the tube there for like half an hour, and oddly the reading was now like 5ppm.

Any ideas why this might be? Which measurement should I trust more?

Thanks!

 

[Maggie321]

The one that you followed the directions

So, last night when I was measuring nitrate with the salifert kit, I followed the instructions and after the time mandated by the instructions (IIRC 3 minutes) my nitrate was reading 2.5ppm.

I left the tube there for like half an hour, and oddly the reading was now like 5ppm.

Any ideas why this might be? Which measurement should I trust more?

Thanks!

 

[Randy Holmes-Farley Verified Community Expert]

Yes, timing can be important for color matching kits, and even temperature, so if you get a result that differs at longer or shorter times, that’s not unexpected for many kits. Some kits even suggest timing changes as the water temp changes.

 

[VR28man]

Very good to know. Thanks, folks!