Milwaukee MW100 PH meter

Portable pH meter with a separate electrode on a cable. Rugged, simple, and built to last years.

The Milwaukee MW100 is a meter without frills: 0.0 to 14.0 pH, resolution 0.1, and manual temperature compensation. The SE220 electrode sits on a cable rather than fixed to the housing, which means you can measure in a deep reservoir without putting your hand in it.

It ships complete, with electrode, pH 7.01 buffer, screwdriver, 9V battery and instructions. Around 300 hours per battery.

Manual or automatic temperature compensation

This meter compensates for temperature manually, and that is the feature separating it from the pocket meters. It is worth knowing what that means.

The voltage a pH electrode produces depends on the temperature of the liquid. The same solution measured at 15 °C and at 25 °C gives a different voltage, and therefore a different reading without correction. Compensation is that correction.

With automatic compensation a temperature sensor inside the meter handles it. With manual compensation you tell the meter what temperature you are measuring at, and it corrects using that figure.

Manual is not a shortcoming as long as your conditions are stable. A reservoir in a grow room typically sits between 18 and 22 °C, and setting it once then covers your whole crop. It only becomes awkward when your temperature swings. Outdoor water in spring, or a reservoir that warms by day and cools at night. Then you have to adjust, and if you forget, you measure crooked.

Practical rule: always measure at roughly the same temperature and set the meter to it. Manual compensation is then just as reliable in practice as automatic.

Technical Specifications:

• pH range: 0.0 to 14.0 pH
• Resolution: 0.1 pH
• Accuracy: ± 0.2 pH
• Temperature compensation: manual
• Electrode: SE220 (included)
• Operating temperature: 0 to 50 °C, max. 95% relative humidity
• Battery: 1 x 9V (included), approx. 300 hours continuous use
• Dimensions: 145 x 80 x 40 mm
• weight: 220 g

Frequently asked questions

Why a meter with a separate electrode?
Because you can then measure in a deep or narrow reservoir without holding the meter in the water, and because the electrode can be replaced on its own when it is finished.

Is 0.2 accuracy enough?
For soil and coco, usually. If you want to steer more sharply, look at the MW101, which reads to 0.01 resolution with 0.02 accuracy.

How do I set the temperature?
You measure your solution's temperature and set that value on the meter. If you always work at about the same temperature, it is a one-off.

Can I replace the electrode?
Yes, the SE220 is available separately. Always recalibrate after replacing it.