Aqua Master P50 Pro2 pH Meter - Waterproof pH & Temperature Pen

Stop Guessing Your Feed pH with the Aqua Master P50 Pro2 pH Meter

The Aqua Master P50 Pro2 is a waterproof pH pen that reads pH and temperature in your reservoir, nutrient tank or watering can, accurate to ±0.1 pH. It calibrates itself, corrects for temperature, runs on two AAA batteries and floats if it ends up in the tank.

Why You Need It

pH decides whether your plants can use the feed you've paid for. Hydro and coco feeds typically run at pH 5.5 to 6.5. Drift outside that and nutrients lock out at the roots, so the plant goes hungry in a tank full of food. And because nutrients shift pH the moment they hit the water, you need to check every mix.

Is the P50 Pro2 Right for Your Setup?

• First pH meter: automatic calibration and a 30-day reminder leave very little to get wrong.
• Need EC too? This pen doesn't measure feed strength. Add the Aqua Master E50 EC Meter, or get both in one with the P110 Combo Pen.
• Testing straight into coco or soil? It reads liquids, not media. Call us and we'll point you to a substrate meter.

How the P50 Pro2 Works

The glass bulb at the tip reads how acidic the solution is, and a built-in sensor applies ATC (automatic temperature compensation, which corrects for water temperature) from 0 to 50°C. You can show 0.1 or 0.01 pH. The second decimal helps you spot drift, but accuracy stays ±0.1 pH, so don't chase the hundredths.

Key Benefits

• IP67 waterproof: it floats, so a slip into the reservoir is a fish-out, not a funeral.
• Self-calibrating: it recognises pH 7.00 and 4.01 buffer and sets itself.
• 30-day reminder: the CAL tick disappears when it's due again.
• AAA batteries: no hunting for button cells, plus a low battery warning.
• Replaceable electrode: swap the tip when it wears out, not the whole meter.
• Auto power-off: shuts down after 8 minutes if you forget.

Contains

• 1 x P50 Pro2 meter with protective cap and cap cord
• 2 x 1.5V AAA batteries and user manual

Not included: pH 4 and pH 7 calibration solutions and KCl storage solution.

P50 Pro2 Specifications

pH range	0.0 to 14.0 pH
pH accuracy	±0.1 pH
pH resolution	0.1 or 0.01 pH
Temperature	0 to 50°C, ±1°C
Calibration	Automatic 2-point, pH 7.00 and 4.01
Waterproof rating	IP67, floats
Power	2 x 1.5V AAA, included
Size and weight	230 x 43 x 43mm, 132g
Warranty	1 year meter, 6 months electrode

How To Use the P50 Pro2

1. Soak it: before first use, stand the electrode in tap water for at least 12 hours.
2. Calibrate: dip in pH 7.00 buffer at 25°C, wait for a steady reading and hold CAL for 5 seconds. Rinse and repeat with pH 4.01.
3. Mix your feed: set your EC first, because nutrients move pH.
4. Test and adjust: dip the pen upright, stir gently, then add pH up or down a little at a time until you're in range.
5. Store it wet: rinse, add a few drops of KCl storage solution to the cap and stand it upright.

Top tip: More pH pens die from bad storage than faults. Never leave the electrode dry or in RO, distilled or deionised water. Pure water strips the reference liquid inside and your readings go wandering.

FAQs

What's the difference between the P50 Pro and P50 Pro2?
The Pro2 adds AAA batteries, a white-on-black display, the 0.01 pH option and the 30-day reminder. It takes the same replacement electrode as the Pro.

There's white crust on the electrode. Is it faulty?
No. Dried salts on a new electrode are normal, and the 12-hour soak dissolves them.

Why does my reading keep jumping?
Usually air bubbles, low batteries or electrical interference. Stir gently, change the batteries and test away from ballasts and other electrical kit.

Need help choosing? Call our growing experts on 01782 749955 or visit One Stop Grow Shop Stoke at Fenton Trade Park.

Get pH right and every bottle of feed works harder. Browse our full range of pH and EC meters.