I just got the black combo one, the most $ so its got all the right stuff.
Highly recommended, i also have a blue lab and a hanna with the wand.
ITs mostly how u treat them and store them for long term life
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In my opinion Hanna is a fine company however recently there has been an influx of returns on their pens. It is commonly a user error however these are the same users who are using Bluelab and not ever bringing them back. I was using a Bluelab about three times a day on 9 nute tanks and when the calibration reminder check mark ( great feature) went away, to my surprise the meter was only .o1 off. If it were me I would spend the extra money on the Bleulab. You will save yourself a headache and possibly a few trips to the hydro store .