Milwaukee MW806 Max 4-in-1 Combi meter

Portable combi meter reading pH, EC, TDS and temperature from a single electrode, storing values and exporting them to your computer over USB.

The Milwaukee MW806 Max is built around one idea: no more juggling separate meters and electrodes. A single MA852 combi electrode reads all four values, with automatic temperature compensation and a stability indicator showing when a reading has settled. The housing is IP67 and the whole thing weighs 260 grams with batteries.

The TDS factor is adjustable between 0.40 and 0.80: 0.50 by default, so you can match it to whichever feed schedule you follow.

Why logging is worth more than measuring

This is the feature that sets this meter apart, and precisely the one most buyers overlook.

A single reading is a number without meaning. Knowing your EC is 1.8 this afternoon tells you nothing on its own. You do not know whether it came from 1.6 or from 2.1, and that is the only part that informs you. Almost every decision in growing depends on a direction, not a value.

In practice growers solve this with a notebook by the reservoir. That works, until you miss a day, until you forget to note what temperature you measured at, or until two months later you want to compare this crop with the last one and the notebook turns out to be half empty.

A meter with a data logger does it for you. You measure, it stores, and you read the series back later or pull it onto your computer. What that gives you:

• You spot drift before it is a problem. An EC that starts higher every crop for three crops running says your top-up routine is wrong. Visible in a series, invisible in single readings.
• You can compare crops instead of relying on memory.
• When something goes wrong, you have a trail. Working out afterwards when a problem started is far easier with data than with reconstruction.
• The GLP button shows when the meter was last calibrated, so you know whether an old reading was trustworthy.

One trade-off is worth stating plainly: everything on one electrode also means one point of failure. If the MA852 goes, you lose pH, EC and TDS at once. The electrode is replaceable, so it is fixable, but with two separate meters you are never blind.

Technical Specifications:

• Measures: pH, EC, TDS and temperature
• Electrode: MA852D/1, replaceable, gel-filled with a cloth junction against fouling, 1 metre cable
• Calibration: automatic pH calibration to up to 5 reference values; EC manual single-point; temperature factory calibrated
• Temperature compensation: automatic
• TDS factor: adjustable from 0.40 to 0.80 (default 0.50)
• Storage: data logger with USB export
• Housing: IP67
• Display: large, with adjustable contrast and stability indicator
• Weight: 260 grams with batteries
• width: just over 7.5 cm

Frequently asked questions

What should I set the TDS factor to?
To whatever your feed schedule assumes. If you do not know, use 0.50 (the 500 scale), or better still, work in EC, where the factor is irrelevant.

What can I do with the USB connection?
Pull stored readings onto your computer to review or keep them, rather than copying them off the screen by hand.

One electrode for everything: does that cost accuracy?
The measurements themselves are independent; they simply share a housing. The real trade-off is not accuracy but risk: one electrode is one point of failure, and you have one thing to maintain properly rather than two.

What is the cloth junction?
A permeable junction protecting the reference solution from contamination. In salt-heavy nutrient solution it makes the electrode last noticeably longer.

Is this suitable for continuous monitoring in a reservoir?
No, it is a handheld. For permanent monitoring, look at a monitor such as the MC811 Max.