Hannah Phosphorous ULR Checker Readings Off

[tingo.bingo]

Hi Yall,

My Hannah Phosphorous ULR checker keeps giving me crazy readings. I rinse in RODI water after tests and wipe with a microfiber cloth before testing. I'm extremely careful in adding the reagent powder. Could the Hanna checker itself be off?

See the results below and notice how far off tests 1 and 2 are from each other most days. I test twice with Hanna and calculate the average, then *try* to confirm with Salifert (impossible to distinguish between colors).

 

[tingo.bingo]

Side note, I have been slowly dosing with PhosphateRX. 6 drops per day in a 55gallon tank, so I was hoping for steady .05 decrease. Getting a bit wary to maybe hold off and make sure my testing is accurate.

 

[xCry0x]

Your last test is the only one that seems to have a meaningful variance from test 1 to 2.

Remember, the tester has a margin of error of +-. 0.02.

It is reading different degrees of water that, to my eye, always appears clear.

I'd trust it way more than any test requiring me to eyeball colors on a chart.

I'd just do a third test if you are really concerned.

 

[elysics]

Question, what do you mean when you say you test twice? Using different vials for the two phases? Using the same vial, testing, dumping it out and redo with new reagent? Using new reagent but with different vials?

 

[jmichaelh7]

I tested last night and was at 2.2 po4

I stressed out for 30 minutes. Then tested again to be sure before I make minor adjustments. I was at 0.06

 

[tingo.bingo]

Question, what do you mean when you say you test twice? Using different vials for the two phases? Using the same vial, testing, dumping it out and redo with new reagent? Using new reagent but with different vials?

I use the two vials the test came with. Test 1 in vial No. 1 and Test 2 in vial No. 2. Same process to find some average.

 

[tingo.bingo]

Your last test is the only one that seems to have a meaningful variance from test 1 to 2.

Remember, the tester has a margin of error of +-. 0.02.

It is reading different degrees of water that, to my eye, always appears clear.

I'd trust it way more than any test requiring me to eyeball colors on a chart.

I'd just do a third test if you are really concerned.

Helpful, thank you!

 

[elysics]

I use the two vials the test came with. Test 1 in vial No. 1 and Test 2 in vial No. 2. Same process to find some average.

Is it always the same vial that reads higher? Maybe one got scratched or discolored from leaving the water with reagent in too long in the past