Using RO water to do analysis

[Gbark]

Hi all,

Some of you are helping me on another thread about Nitrate levels, but i thought i should start a new one for this.

I have just received my new Nitrtate test kit. It measures from 0-15ppm as N

It works by putting 1ml of the test solution into a measuring cylinder, adding 20ml deionized water and then the test agents. Mix and leave to stand, then take 10ml of this solution add a tablet that gives it a colour and then compare.

Well i have been using RO water instead of deionized water.

Today i bought some deionized water from the store and i have done some tests on my water's

I sampled my tank and mixed with my RO water and got a reading of 6ppm N
I sampled my tank and mixed with Deion water and got a reading of 1ppm N
I sampled my RO water and mixed with Deion water and got a reading of 0ppm N

How does this work, it looks like i get a false reading with RO water even though my RO water contains no NO3

 

[Biollante]

Test Stuff

Hi Geoff,

What brand of test kit are you using?

Is this a Cadmium reduction method, followed by Nitrogen-Ammonia/Ammonium salicylate method?

Biollante

 

[Gbark]

Hi Geoff,

What brand of test kit are you using?

Is this a Cadmium reduction method, followed by Nitrogen-Ammonia/Ammonium salicylate method?

Biollante

Its from a company called palintest. (i could not get the lamotte test kit)

We have talked in another thread and we know my RO does contain a small amount of Nitrate.

is it possible that when i add the 19ml of RO water to the 1ml tank sample that the nitrate reading is increased by 19x