What does the COM-300 measure?

It measures pH, TDS, EC, and temperature in one meter, covering pH 0-14 and a combined ±2% accuracy across the EC/TDS/temp ranges. That all-in-one design replaces separate single-purpose testers.

Is the COM-300 waterproof?

Yes, it's rated IP-67 waterproof, meaning it's submersible and floats. That rating matters for a meter that regularly gets dipped into nutrient reservoirs and runoff trays.

How do I calibrate the COM-300?

It uses push-button digital calibration to any point within the meter's range, with automatic temperature compensation (ATC). That calibration method is faster than manual dial adjustment on older analog meters.

Can the sensor be replaced if it wears out?

Yes, the COM-300 uses a replaceable sensor rather than a sealed, disposable unit. That means you can restore accuracy over time without buying an entirely new meter.

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HM Digital pH / TDS / EC / Temp meter

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$151.47 $171.38

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HM Digital pH / TDS / EC / Temp meter

Name: HM Digital pH / TDS / EC / Temp meter
Brand: HM Digital Inc
SKU: DILCOM300
Price: 151.47 USD
Availability: InStock

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Product Code:

DILCOM300

$151.47 $171.38 -12%

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Description
Features
Reviews

Waterproof pH/TDS/EC/Temp Meter with Push-Button Calibration

Testing nutrient solution or runoff with three separate meters wastes time and multiplies the chances of a dead battery mid-check. The HM Digital pH / TDS / EC / Temp meter (COM-300) reads all four in one waterproof, floating handheld.

Sold as one HM Digital COM-300 meter.

Key Features & Benefits

Reads pH, TDS, EC, and temperature — in a single handheld meter with one combined display.
IP-67 waterproof, submersible, and floats — built for hands-on use around nutrient tanks and reservoirs.
Push-button digital calibration with ATC — calibrate to any point in range, with automatic temperature compensation.
Replaceable sensor — extends the meter's working life beyond a single sensor's lifespan.
±2% overall accuracy — across pH 0-14, EC/TDS, and 0-55°C/32-130°F temperature ranges.

Who Should Use the HM Digital COM-300

This fits growers who want a single waterproof meter covering pH, TDS, EC, and temperature instead of carrying multiple separate testers around the grow room.

About the HM Digital COM-300

The COM-300 is HM Digital's waterproof handheld meter for pH, TDS, EC, and temperature, with push-button calibration and a replaceable sensor.

Frequently Asked Questions

What does the COM-300 measure?: It measures pH, TDS, EC, and temperature in one meter, covering pH 0-14 and a combined ±2% accuracy across the EC/TDS/temp ranges. That all-in-one design replaces separate single-purpose testers.
Is the COM-300 waterproof?: Yes, it's rated IP-67 waterproof, meaning it's submersible and floats. That rating matters for a meter that regularly gets dipped into nutrient reservoirs and runoff trays.
How do I calibrate the COM-300?: It uses push-button digital calibration to any point within the meter's range, with automatic temperature compensation (ATC). That calibration method is faster than manual dial adjustment on older analog meters.
Can the sensor be replaced if it wears out?: Yes, the COM-300 uses a replaceable sensor rather than a sealed, disposable unit. That means you can restore accuracy over time without buying an entirely new meter.

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