I've used a number of test kits over the years to measure Phosphate, and my default has been Salifert. The kits costs about $25, and you can test about 50 times before needing a replacement. I test PO4 (Phosphate) all the time, so I know how to use that kit by heart. If the vial is clear, I'm good. If it's blue, oh no! If it is slightly blue, grrr. Yes, those are my reactions to seeing 'algae fuel' show up in a test kit.
At MACNA, I went to the Premium Aquatics booth to buy a new kit, and Jeremy was all out. He recommended the Hanna Checker to me. It's about $50, and includes a few tests. I was told 10, but I didn't get 10 in mine. Knowing how much I test, I asked for two additional boxes of 25-each to have enough for a full year.
In addition to the test, you'll need a plastic syringe, a dry towel and some scissors.
The reagent packets come in Standard or Low Range, so be sure to get the latter (pictured below). HI713-25 is the correct type.
Since then, I've probably used the digital photometer at least a dozen times. It's very easy to use, and I no longer have to guess how blue my vial is against a test card with aquarium lighting throwing off my visual judgement... or forcing me to run outside into the sunlight. Instead of guessing, I have a real number to work with.
Using it is simple. Install the supplied AAA battery in the device's base compartment. Fill up one vial with 10ml of tank water. Clean the vial so it is dry and smudge free. No fingerprints!
To open the lid, you need to squeeze the front and back together slightly to cause it to pop open.
Insert the vial into the Hanna Checker holding it only by the black cap and close the lid.
Fill up the second vial with 10ml of tank water. Carefully cut open a packet of the Phosphate reagent, bending the foil packet to create a sharp-V shape funnel to channel the powder into the vial's narrow neck. Tap the packet to coax all the powder out and into the vial.
Seal the vial with the lid and shake it for two minutes to fully dissolve the crystals.
Once that has been completed, turn on the Hanna Checker by pressing the button on the front.
After a few seconds "C1" will appear. Press the button again so it can calibrate to zero through the first water sample. This may take a few seconds, then "C2" will appear on the screen.
Open the top, and take out the first sample.
The second sample that was shaken for two minutes needs to be completely wiped off, totally dry and smudge free. If you see any tiny bubbles, flick the glass with your fingernail (tink tink tink) to make those rise, and slide it into the device. Bubbles can cause false readings.
Press and hold the button for two seconds, and a three-minute countdown will commence. When it reaches zero, the result will be displayed on the screen.
Here's another shot of the countdown. The colon blinks as well, so the timer was at 2:55 when the picture was taken.
There is no sound to remind you to check it, and the unit times out (powers off) after two minutes so pay attention. Or set a timer nearby to chime a gentle reminder to check the reading.
I have used the Hanna Phosphate Checker with both saltwater as well as fresh water (tap, RO and RO/DI) and have little reason to doubt the readings after two months' worth of testing. It's much easier to know a real number than to take an educated guess with my previous titration kits and comparing the liquid to a color chart.
The Checker will cost $0.50 more per test (compared to Salifert), but it seems worth it to me to get a digital read-out. I'd imagine any Reef Addict would concur.
Here's the official video from Hanna Industries:
POST EDIT 11/1/13:
I may be amending this product review pending further research and testing. I had some water quality concerns based on the results I got from the Hanna Checker that may not have been accurate as one would expect. I documented my findings in this blog: http://www.reefaddicts.com/entry.php...e-embarrassing
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