Hanna 96713 Reading - Which is Accurate?

[Hair Algae Wizard]

Folks,

I have a Hanna HI 96713 Low Range Po4 photometer, and unsure of which reading is correct. The included cuvette is marked at 10m/l, but is not accurate. I have tried testing both using the 10m/l level marked on the cuvette, and filling the cuvette with a digital pipette set to 10m/l. I get the following readings:

Using 10 m/l on cuvette: Po4 is 0.01
Using pipette: Po4 is 0.04

Any ideas on which reading to trust? Disappointed that Hanna provides an inaccurate measurement.

Any advice is appreciated!

 

[MnFish1]

Folks,

I have a Hanna HI 96713 Low Range Po4 photometer, and unsure of which reading is correct. The included cuvette is marked at 10m/l, but is not accurate. I have tried testing both using the 10m/l level marked on the cuvette, and filling the cuvette with a digital pipette set to 10m/l. I get the following readings:

Using 10 m/l on cuvette: Po4 is 0.01
Using pipette: Po4 is 0.04

Any ideas on which reading to trust? Disappointed that Hanna provides an inaccurate measurement.

Any advice is appreciated!

Hopefully this helps. 1. Its a little unclear what does m/l mean? 2. Every measurement has an 'error' - so - how do you know that the digital pipette is not the inaccurate measurement? 3. If you look at the Hanna website, the accuracy is

Phosphate, LR Accuracy	±0.04 mg/L ±4% of reading

So - I would suggest - a couple things. 1). Just follow the directions on the test kit you bought. Don't use digital pipettes or other ways to measure. 2). Given the accuracy of the test your using - I'm not sure there is a statistical difference between the measurements. 3) I'm also not sure there is a 'significant' difference between the .01 and .04 from your tanks perspective. But - I guess - I would trust the test that you did by following the instructions - as compared to the pipette. You could also do 3 measurements and average the results.

Hope this helps.

 

[Hair Algae Wizard]

Hopefully this helps. 1. Its a little unclear what does m/l mean? 2. Every measurement has an 'error' - so - how do you know that the digital pipette is not the inaccurate measurement? 3. If you look at the Hanna website, the accuracy is

Phosphate, LR Accuracy	±0.04 mg/L ±4% of reading

So - I would suggest - a couple things. 1). Just follow the directions on the test kit you bought. Don't use digital pipettes or other ways to measure. 2). Given the accuracy of the test your using - I'm not sure there is a statistical difference between the measurements. 3) I'm also not sure there is a 'significant' difference between the .01 and .04 from your tanks perspective. But - I guess - I would trust the test that you did by following the instructions - as compared to the pipette. You could also do 3 measurements and average the results.

Hope this helps.

Thank you, and I appreciate the reply. Oh, and M/L was my error. It should be ml.

 

[MnFish1]

Thank you, and I appreciate the reply. Oh, and M/L was my error. It should be ml.

I kind of thought you meant ml. I use a syringe to fill my cuvettes - but I do not use the measurement on the syringe - I use the cuvette. The syringe is just for convenience

 

[Dan_P]

Folks,

I have a Hanna HI 96713 Low Range Po4 photometer, and unsure of which reading is correct. The included cuvette is marked at 10m/l, but is not accurate. I have tried testing both using the 10m/l level marked on the cuvette, and filling the cuvette with a digital pipette set to 10m/l. I get the following readings:

Using 10 m/l on cuvette: Po4 is 0.01
Using pipette: Po4 is 0.04

Any ideas on which reading to trust? Disappointed that Hanna provides an inaccurate measurement.

Any advice is appreciated!

One more thing. The contents of the phosphate reagent packets vary in weight, so, the slight inaccuracy in the vial volume is probably unimportant. Tiny variation in measured values are noise. 0.01 is not different from 0.04 ppm. This is normal.