The Hanna Phosphate Checker allows you to get a digital reading instead of having to judge the color of the mixed reagents in a vial.
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