Only problem is the resolution and accuracy. From what I understand the goal in saltwater is to aim for a phosphate level below 0.05ppm so using this device doesn't really work for people in the right range, only those outside of it. However probably still better than most test kits so for $40, not too bad.

your right...my phosphates are below the bottom end of the tester

I was wondering about the accuracy ±0.04 ppm (mg/L) ±4% of reading @ 25°C.
But that is the same Hanna's other more expensive unit.
So not sure what the difference is between the 2, but only the price.

It would be nice to have the accuracy explained for these meters. I take it to mean ±4% up to a maximum of ±0.04 ppm within the meter's range. An accuracy of ±0.04 ppm for a reading of 0.01 ppm would be... strange.

This is the exact same resolution and measurement error as the more expensive unit. I've always found it funny that people have used them and touted them as the "holy grail" for phosphate testing and now people are claiming the measurement error is too high on this one. Evidently they weren't paying attention to the literature on their pricier model. The resolution of 0.01 and measurement error of 0.04 is totally reasonable. What it means is that you can only reasonably assume your phosphate is somewhere between 0.00 and 0.04 when you get a reading of 0.00. When you get a reading of 0.03 (typical targeted value) you can only assume you're somewhere between 0.07 and 0.00. If you have a reading of 0.10 then you can reasonably assume you're somewhere between 0.14 and 0.06.

Go
 

well put!
________
Lenya