Bluelab pH PenPlus & Replacement pH ProbePlus

One Stop Grow Shop never disappoints. (Note: While this review is for a product listed on GroWell, it was sold and dispatched by OSGS). ​The pen itself is outstanding quality, exactly as you’d expect from Bluelab. My previous Bluelab pen lasted for years before finally giving up the ghost. I briefly tried switching to Hanna Instruments as a replacement, but that experience only proved to me that there is absolutely no better brand for plant water quality testing than Bluelab. Highly recommended. This particular product has made things even better, Bluelab AND replaceable electrodes? Yeah, honestly, look no further.