New Hanna phosphate checker

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I got my Hanna phosphate checker today. I have not had time to fully assess it, run comparisons against my current phosphate test kit etc. but here is what I have found so far.

The phosphate checker comes in a plastic carrying case which snaps shut extremely tightly. You need a knife or screwdriver to pry the case open. Similarly you will need to poke the prong of a fork into the bottom of the phosphate checker to open the battery compartment and insert the battery. Fortunately I did my testing in the kitchen so plenty of utensils were available.

The instructions are incorrect. I was unable to get a phosphate reading by following the included instructions. Specifically the instructions say to wait three minutes for the reaction to occur then press the button to get a reading. If you wait three minutes the unit turns itself off and you will need to start over again from step one.

The instructions also give a second method of measuring the phosphate, using the built-in timer. After the timer gets to three minutes, the phosphate level is supposed to display. It does not display, and after ten more seconds the unit turns itself off. To get a phosphate measurement you need to press the button again after the timer counts down three minutes.

The reagent powder comes in individual pre-measured packets. This is good. It saves the trouble of measuring and it eliminates a potential source of error.

There is no information in the instructions regarding how safe or hazardous the reagent powder is. I would like to know this because the precautions I take (gloves, location of the test, cleaning up afterward) will vary depending on what the reagent is.

Once I figured out how to get the thing to work, it is not too complicated to do the phosphate test.

1. Fill the vial up to the line with aquarium water. No pipette is included so you need to use one from another test kit.

2. Put the cap on the vial and clean off the outside of the vial with a cloth.

3. Press the button on the phosphate checker and wait until it tells you to insert the vial.

4. Insert the vial into the phosphate checker, close the lid, press the button again, and wait a few seconds for the sample to calibrate to zero.

5. Take the vial out of the phosphate checker and pry the cap off the vial (difficult to do).

6. Add one packet of reagent. Put the cap back on and shake it for 20 seconds (the instructions say not to shake it but just swirl it so as to avoid air bubbles, if you do this the reagent won't dissolve).

7. Put the vial back into the tester, close the lid and then hold the button down until the timer starts.

8. Wait for the 3 minute timer to end, then press the button to see the phosphate value displayed. If you wait more than 10 seconds to press the button, the checker will turn itself off and you will have to start again from the beginning.

My reef tank tested at 0.00 ppm phosphate, and my plant tank tested at 1.15 ppm phosphate. I don't know if these measurements are accurate or not. When I have more time I will compare them against my Merck phosphate test kit, and also run several tests in a row on the same sample to see how consistent the measurements are.

Overall the main advantage to this checker is you don't need to guesstimate a colour match like you do with a conventional phosphate test. Particularly at low to zero phosphate values, my Merck test kit is very difficult to make a visual match to the colour chart to make a phosphate measurement.

Things I would like to have seen done differently with the Hanna phosphate checker:

1. Make instructions that work correctly. I wasted 3 packets of reagent before I figured out how to get a measurement.

2. Make a case that can be opened by hand, not pried open with a knife.

3. Include a pipette to draw up the water sample.

4. Get rid of the "turn off after 10 seconds" feature, this is annoying, an auto shutoff after a minute or two is more reasonable.

5. Add an audible "beep" alarm when the 3 minute reaction time is over.

The bottom line is despite some non-user-friendly features and poor instructions, if this unit turns out to make accurate phosphate measurements then it will be an improvement over the other (visual comparison based) phosphate test kits out there.

If anyone has time to do more detailed testing on this machine, or particularly if someone has access to laboratory equipment to accurately test phosphate levels to compare to the Hanna phosphate checker, it would be good to make an assessment of the accuracy of the phosphate checker.