The AC Infinity Hydroponic Meter PRO Kit is an all-in-one water tester: one pen, one probe, reading pH to ±0.01 plus EC, TDS, salinity and temperature. The probe is interchangeable, the body is sealed to IP67, and the kit includes pH and EC calibration solutions with KCL storage solution. It replaces a separate pH pen and EC meter with a single tool. Genuine AC Infinity, stocked in Sydney and shipped domestically.
All-in-one testing kit
Every nutrient mix needs two answers: is the pH in range, and is the solution the right strength. This pen gives both from one dip. Switch modes to read EC in µS or mS, TDS in ppm, or salinity, with water temperature on screen the whole time. EC auto-ranges across 0–200 µS, 200–2,000 µS and 2–20 mS, which covers everything from tap and RO water to a full-strength feed.
The TDS conversion factor is adjustable from 0.40 to 1.00 (factory default 0.71), so the ppm reading can be matched to whichever scale your nutrient chart uses. Temperature compensation is adjustable too, with a 2.00% default.
Lab-grade precision
The lithium glass membrane settles to a pH reading in seconds, at ±0.01. pH calibrates at 1, 2 or 3 points; EC calibrates at 1413 µS, with an optional second point at 12.88 mS for strong solutions. Both EC solutions and the 4.00 and 7.00 pH buffers are in the box, and the KCL solution keeps the glass wet in storage.
Replaceable design
The probe is the wear part on any pH meter; AC Infinity put its average life at about 18 months. Here it unscrews from the pen and a new probe (AC-PPA7) screws in with a sealed fit, so the meter keeps going. Ask us about a replacement probe when you need one.
Which AC Infinity pen?
| pH Meter Kit | pH Meter PRO Kit | Hydroponic Meter PRO Kit | |
|---|---|---|---|
| Model | AC-PHM3 | AC-PHM5 | AC-PHM7 |
| Reads | pH, temp | pH, temp | pH, EC, TDS, salinity, temp |
| pH accuracy | ±0.1 | ±0.01 | ±0.01 |
| Probe | Fixed | Interchangeable | Interchangeable |
Only need pH? The pH Meter PRO Kit has the same ±0.01 probe. Want the readings logged around the clock instead of spot tests? See the AC Infinity AI Hydro Sensor.
Specifications
| Product identification | |
| Manufacturer | AC Infinity Inc. |
| Product name | Hydroponic Meter PRO Kit |
| Model | AC-PHM7 |
| UPC | 819137024212 |
| Performance and technical | |
| Sensor | pH, EC, TDS, salinity, temperature |
| Probe | Interchangeable lithium glass membrane, with sensor shield |
| pH accuracy | ±0.01 pH |
| EC ranges | 0–200 µS, 200–2,000 µS, 2–20 mS |
| TDS factor | Adjustable 0.40–1.00 (default 0.71) |
| Calibration | pH 1, 2 or 3 point; EC 1413 µS, optional 12.88 mS |
| Included solutions | 4.00 pH, 7.00 pH, 12.88 mS, 1413 µS, KCL storage (use-by April 2026, see note above) |
| Ingress rating | IP67 |
| Auto off | After 8 minutes of inactivity |
| Dimensions | 4.2 × 3.3 × 17.8 cm (1.65 × 1.30 × 7.01 in) |
| Replacement probe | AC-PPA7 |
| Documentation | |
| User manual | pH Meter PRO / Hydroponic Meter PRO manual (PDF) |
| Calibration | Calibration instructions (PDF) |
| Warranty | 6 months on the meter, from date of purchase. Calibration and storage solutions are consumables and are not covered. |
FAQ
Is the included solution OK to use?
It is past its April 2026 use-by date, which is why the kit is reduced. For readings you rely on, calibrate with fresh pH 4.00 / 7.00 and 1413 µS solution. Solutions are consumables, inexpensive and easy to buy, and are not covered by the meter's warranty.
Does one probe really do pH and EC?
Yes. The probe carries the pH glass membrane and the conductivity cell together, and the pen switches between readings. Calibrate pH and EC separately with their own solutions.
My nutrient chart is in ppm. Will the numbers match?
They can. Charts use different conversion scales (commonly 0.5 or 0.7). Set the pen's TDS factor to the scale your chart uses, or work in EC, which is the same everywhere.
Is it accurate enough for a strong bloom feed?
Yes. EC reads up to 20 mS, well above any nutrient solution. For best accuracy at the top end, add the optional 12.88 mS calibration point.
Can I leave it in the reservoir?
No. It is a handheld pen for spot tests. For a probe that stays in the water and logs continuously, see the AC Infinity AI Hydro Sensor.
How should I store it?
Wet. A few drops of KCL storage solution in the cap, cap on, rinse with clean water before the next reading. Never wipe the glass bulb.
