Apera Instruments AI101G GroStar Series GS1 pH Pen Tester Kit with Replaceable Double-Junction pH Probe for Hydroponics Water Quality Testing, Gen II

State-of-the-art pH sensor tech

• The GroStar pH probe is featured with a anti-contamination double-junction reference system and blue gel inner electrolyte along with a lithium glass membrane, allowing you to easily take accurate pH measurement in the long term.
• The probe is replaceable just so you only need to replace the probe when it reaches its end of life instead of buying a whole new tester.

TruRead Measurement Mode

In TruRead mode, the pen can automatically record pH measurements after the reading is stabilized for 7 seconds and show you the average, maximum, and minimum values of all the recorded measurements.

Grower-friendly Auto. Calibration

The grower-friendly auto. calibration workflow allows you to finish 2-point calibration within a minute. M or L icons will appear after calibration to let you know the meter is successfully calibrated, and will disappear in 30 days to remind you to re-calibrate.

Electrode Condition Display

After finsihing the 2nd point calibration, the slope data of the pH electrode will show up, indicating the health condition of your pH electrode. The closer the slope is to 100%, the better the electrode's conditon is. In general, we would consider 97% to 100% as great condition, 93% to 96% as good condition. If below 90%, it means your pH electrode is close to its end of life, and we recommend replacing it to ensure the optimal measurement accuracy.