The trouble of the sensor of the compact pH meter used until now was assumed, so when we replaced it with this product, we were able to obtain stable values. Although it is saved if it is a little cheaper.
At the beginning, when used for about 6 months, the electrode part was colored (darkened) and the value showed distinctly different values compared with other pH meters, so the life span? Judge and exchange. Although I will not darken even afterwards, the value has no credibility and it is disposed of. A nice thing is that the standard solution needs only a small amount. (It is no longer calibrated even if the calibration solution is changed to a new one)