Nitrate - Hanna colorimeter or Pinpoint monitor?

[untamed]

Which device is going to give me my most accurate, low range, readings on nitrate....the Hanna Colorimeter...or the Pinpoint Monitor?

http://www.americanmarineusa.com/nitratefacts.html

http://hannainst.com/usa/prods2.cfm?...ode=HI%2093728

I suspect that few people have used the colorimeter and that the monitor is more widely used.

I think the colorimeter will cost less up front, but run $.60 per test. The nitrate monitor will cost more, have little usage costs...but I wonder if the probe ever needs to be replaced...?