Haana Nitrate Checker accuracy poor?

[strich]

I've been slowly fighting down high no3 and po4 in my tank since I got it at the start of the year - it's a high fish load system so not super surprising. I've been using the hanna nitrate HR for some time now and I'm getting a little worried about the variation of numbers I'm getting.

On average my nitrates are or were trending down from 65ppm. A few weeks back I got a surprise 45ppm, then 60ppm then ext day which is more what I expected.

Today I got another 45ppm result and so I grabbed the vial out gave it a few turns then immediately retried the test without the 7 min wait and it reported 49. Then 54 a few mins later again. It does seem it is highly time sensitive and there is a vast difference between even a few minutes. Does that seem right? I know it takes time IE the 7 min wait on the test itself plus 2 mins mixing time before that. But surely by then it's hit an equilibrium ?

One final note - unlike the po4 test powder which slides out cleanly from the sachet I find the no3 powder leaves an amount behind. Would this not skew the tests? I have observed this across different batches of sachets by now.

 

[Fish Fan]

I'm sorry that you're having some trouble.

I know that Randy Homes-Farley has commented that it's not important to get every last grain of reagent out of the Hanna pouches. Here's a very recent post of his confirming this:
https://www.reef2reef.com/threads/a...ect-nitrate-measurement.1173771/post-14584375

I hope this helps!