Milwaukee MC110 pH monitor

Sits permanently in your reservoir and warns you the moment acidity leaves the limits you set. Runs on an adapter, so no batteries.

The Milwaukee MC110 is not a handheld but a monitor: it keeps measuring. You set your own upper and lower limit between 3.5 and 7.5 pH, and an LED alarm flashes as soon as the value falls outside them. Supplied with a 12V adapter, mounting kit, electrode holder, a double-junction electrode on a 2 metre cable and a starter bottle of pH 7.01 buffer.

What a monitor sees that a pen misses

A handheld gives you a snapshot. You measure, you note a number, and that number applies to that one moment. What happened during the twenty hours in between, you do not know.

And that is the problem, because pH in a recirculating system does not sit still. It moves with plant uptake, with temperature, with the day-night cycle. A reservoir reading 5.9 in the morning and 5.9 again at night may well have sat at 6.6 in between, and those excursions are what cost you yield, because uptake stalls during those hours.

A monitor sees that, and more importantly, it makes noise about it. The setpoint is the reason you buy one. You do not have to watch it; it only asks for your attention when there is something to see.

Where this pays off most:

• Recirculating systems where one reservoir feeds every plant, so one value going astray hits all of them at once.
• Large water volumes you do not change daily.
• Automatic dosing, where a dosing fault becomes visible before it does damage.
• When you are not always there. An alarm going off while you are out still beats finding out afterwards.

Note the accuracy: 0.2 pH. A monitor is built to flag movement and limit breaches, not to base your finest adjustment on. For precise correction you use your handheld; the monitor tells you when that is needed.

Technical Specifications:

• pH range: 0.0 to 14.0 pH
• Resolution: 0.1 pH
• Accuracy: ± 0.2 pH
• Calibration: manual, 2 points
• Alarm setpoint range: 3.5 to 7.5 pH
• Alarm: optical LED alarm on breach, high or low
• Electrode: MA911B/2, double junction, 2 m cable, BNC connector
• Power: 12V adapter (included)
• Supplied with: mounting kit, electrode holder, 20 ml pH 7.01 buffer

Frequently asked questions

Can it dose pH down by itself?
No. This monitor measures and alarms; it controls nothing. Correcting is up to you.

Can the electrode stay in the solution permanently?
Yes, that is what it is for. It does shorten its life compared with a probe used occasionally. Expect to replace it once calibration no longer holds.

Why an adapter rather than a battery?
Because on continuous duty a flat battery fails at exactly the wrong moment. On mains power it keeps running.

Does this replace my pH pen?
No, they complement each other. The monitor watches; the pen measures accurately when you correct.