Hanna Waterptroof pH Pen HI 98127 pHep4

Maintaining a hydroponic reservoir can be made easier with Hanna's Digital pH Pens. These pens feature a large LCD, renewable cloth juntion, and a replaceable electrode. The pHep4, features a waterproof casing and is 100% buoyant. The dual level LCD gives temperature readings in both Celcius and Farenheit and battery level reading.  All models have a replaceable electrode, Automatic Temperature Compensation (ATC) as well as automated calibration and shut-off. We recommend that all pH pens be calibrated at least weekly to ensure accurate readings. It it recommended to use Hanna 7.0 and Hanna 4.0. These units ship with a single use packet of both 4.0 + 7.0.