Bests & Worsts Reviews from Amazon

Straight out of the box it's not calibrated. It reads a mixed up pack of 6.86ph buffer solution as 6.50ph. See my picture. I also tested a glass of water 3 times over an hour and got 3 differient readings. First time it read: 5.52ph Second time it read: 5.69ph Third time it read: 5.72ph It may not seem like much but that can be a BIG difference depending on what youbwere needing an accurate ph reading for. I bought this because if my 2 year old "Jellas" brand was working properly. But it still gives the same read out (6.2ph) as it did a week ago on the same water. I don't like the style of calibration either. I've only ever seen the type where you turn the little screw on the back and dial it to read what the buffer solution should be. How do I know what is pre-programed onto the memory circuit is accurate in the first place? And what if I only have a 4.0ph and a 6.86ph pack of buffer solution? Does that mean I can't calibrate unless I have all three? Not cool. I like being able to calibrate with just one or two calibration levels, if that's all I have on hand at the time. I'm going to try another brand.