The phosphate meter is a VERY good piece of equipment but it may not be for everyone.
I'm actually debating whether or not I want to sell mine (probably won't though).
Here's the only downside to the meter that I have run across.
The meter displays readings down to the hundreths.
We want our phosphate readings at or below .02 (debatable).
This meter will do the job since it can give you a reading of .02, .01 and .00
For the most part, this will satisfy most reefers demands.
If you want readings any more accurate than this then you have a problem since this meter can not do it.
HOWEVER, there is a regular test kit on the market that can give readings that are more in depth than the Hanna meter.
The Low Range Phosphate Test Kit from D-D Aquarium Solutions. It's a very pricey test kit as it will set you back about $75 for 100 tests BUT it gives you detailed readings down to the thousandths and is easy to use with easy to see color changes for the different readings.
Hmmm - Sitting down and writing this comparison up made me take a close look at the two together and actually ended up throwing a monkey wrench into my thinking. I was pretty well convinced that the D-D test kit was the way to go but now I'm not sure if there really is much of a difference at all.
WHY?
The Hanna meter gives you 3 results that are OK (basically): .02, .01 and .00
What I just realized is that with the D-D test kit, even though it gives more precise readings, there is still only 3 results that are OK (basically): .015, .008 and .000
So is the D-D kit really any better? I don't know.