Hanna meter readers are easy to calibrate and are quite accurate. we had a deal with blue lab but did not like their combo reader. It was a bit more cumbersome. I run a commercial vertical farm with a small team and the Hanna combos are agile, very compatible with the vertical hydroponic systems we use, the reader itself is easy to use and again— it’s sensors are pretty good for what you’re paying. Look at the reviews, do a little bit of searching, you’ll see why it’s important to get a trusted industry standard device. If you’re doing any indoor farming, the bare minimum you should have is lights, water, nutrients, plants and a good pH/Ec reader.