Test kits

[guitarbomber]

Hi,
I tested with my Hanna phosphate UL kit,
Waited 2 minutes while it shook then pressed the button to wait 3 minutes, it tested INV,
I then did it again with a different regent it read 0.00,
I then put the first vial back in and short pressed it and it read 0.07, what readings should I take? Am I better shaking the vial for 5 minutes then doing a short press?
Any help?

 

[Dan_P]

Hi,
I tested with my Hanna phosphate UL kit,
Waited 2 minutes while it shook then pressed the button to wait 3 minutes, it tested INV,
I then did it again with a different regent it read 0.00,
I then put the first vial back in and short pressed it and it read 0.07, what readings should I take? Am I better shaking the vial for 5 minutes then doing a short press?
Any help?

If you did not let the shaken sample sit for 3 minutes, then suspended particles likely caused the 0.07 reading. 0 ppm might be the true result.