With those Hanna meters make sure you use the right calibration solution, only the packets that come with it. GH has a ppm calibration fluid and I guess it doesnt work with them. I use the 1500 ppm solution and its fine. It does take a while so leave it in there for a couple of minutes.
altaholic Reviewed by altaholic on . how to calibrate ppm on hanna hi98129 do i use the 1413us/cm solution or the 1500 ppm solution to calibrated Rating: 5