AC Infinity Digital pH Meter Kit

AC Infinity's entry kit: a pH and temperature meter with pH 4.00 and 7.00 buffers included. IP67 waterproof, with a probe guard.

The AC Infinity Digital pH Meter Kit reads acidity to ± 0.1 pH and measures water temperature alongside it. The probe uses a lithium-glass membrane and the housing is IP67. Fully dust-tight and good for temporary submersion, which matters in a grow room full of condensation and splashes.

More important than the meter itself is what comes with it: two ready-to-use buffer solutions, so you can calibrate at two points immediately instead of having to buy bottles separately first.

Calibrating, step by step

Almost everyone calibrates too quickly or in the wrong order, and the result is a meter that is confidently wrong. Here is how to do it properly:

1. Let your buffer reach room temperature. Solution out of a cold shed calibrates your meter crooked, because the buffer's own pH shifts with temperature.
2. Pour a small amount into a clean pot. Never calibrate in the stock bottle: your tip always carries something with it, and that contaminates your whole supply.
3. Rinse the tip with clean water and tap it dry. Do not wipe it with a cloth: the membrane is thin glass and scratches.
4. Start at 7.00. That is your zero point. Hold the tip in, stir gently, and wait until the value stops moving. That takes longer than you expect: ten to thirty seconds is normal.
5. Rinse again and go to 4.00 for the second point. That corrects not only the zero point but the slope, which is what makes your reading trustworthy in the range you actually work in.
6. Throw used buffer away. Pouring it back is the fastest way to ruin your next calibration.
7. Store the tip wet. Dry storage is what most probes die of.

Repeat monthly, and always after a drop, after a long idle spell, or the moment you distrust a reading.

Technical Specifications:

• Model: AC-PHM3
• Measures: pH and temperature
• Accuracy: ± 0.1 pH
• Probe: lithium-glass membrane
• Protection rating: IP67, dust- and waterproof
• Dimensions: 4.2 x 3.0 x 17.8 cm
• Kit contents: pH meter, pH 4.00 and 7.00 buffers, probe guard

Frequently asked questions

What is the difference from the pH Meter PRO Kit?
Three things, and they are worth weighing. The PRO gives ± 0.01 instead of ± 0.1, has a replaceable probe, and includes KCl storage solution plus a third buffer. That replaceable probe is the strongest long-term argument: a probe is a consumable, and if it comes out you replace a part rather than the whole instrument.

Is ± 0.1 accurate enough?
For soil and coco, comfortably. In those media the medium buffers small differences away. In hydroponics and rockwool, where there is no buffer, you want to steer more sharply.

Is storage solution included?
No, only the two buffers. KCl storage solution is available separately and strongly recommended. It is the difference between a probe lasting a season and lasting years.

Can I use it for my pool or aquarium?
Yes. The meter simply reads the acidity of water; the application does not change it.

Does it measure EC as well?
No, pH and temperature only. For pH and EC in one device, look at the Hydroponic Meter PRO Kit or a combi meter.