Phosphorus ULR mixed results

[goober]

Hello I am getting some mixed results when running multiple tests using my checker. I have tried this twice approx. one week apart.

When doing my tests I fill 2 vials with 10ml water. With one vial I do the complete test and have had a result of 8 pbb. Then I repeat the test using the 2nd vial as the "base" then insert the 1st vial when it prompts for c2 and I get a result of 1 pbb. The 3rd time I do this it comes up as 0 pbb.

First run: 8 pbb
Second run: 1 pbb
Third run: 0 pbb

Both times I did this it produced similar results and now I don't know what to trust?

 

[Dogtown]

Percentage wise, the numbers are very close. If the reading were ppM, all three results would have been <=1ppm. Pretty good for a hobby grade test kit. I use it to know if my numbers are low, med, high.

 

[goober]

Percentage wise, the numbers are very close. If the reading were ppM, all three results would have been <=1ppm. Pretty good for a hobby grade test kit. I use it to know if my numbers are low, med, high.

Oh I completely agree I am more interested if the reading of 1 and 0 after the initial test of 8 are valid. I do not wish to have a reading of 0 lol