HM Digital COM-80 EC/TDS/Temp Waterproof Hydro Tester

Waterproof Combo Meter for EC, TDS, and Temperature

Carrying separate meters for conductivity and temperature means extra gear and extra room for error when the two readings don't line up. The COM-80 folds electrical conductivity, total dissolved solids, and temperature into one waterproof meter, reading across four scales (uS, mS, ppm, ppt) on a single large LCD.

Automatic temperature compensation adjusts EC/TDS readings as water temperature changes, and digital push-button calibration lets you recalibrate to any point in the meter's range rather than a single fixed factory setting.

Key Features & Benefits

• EC and TDS on four scales — µS, mS, ppm, and ppt, so you can read in whichever unit your nutrient program uses.
• Automatic temperature compensation — adjusts conductivity readings as water temperature shifts, so you're not chasing a moving baseline.
• Water-resistant housing — holds up to the wet conditions common around reservoirs, flood tables, and drain lines.
• Digital push-button calibration — recalibrates to any point in the meter's range rather than a single fixed factory setting.

Who Should Use This Meter

Hydroponic growers, gardeners, and hobbyists who want one waterproof meter for EC, TDS, and temperature instead of juggling separate testers for pools, aquariums, spas, or drinking water.

About HM Digital

HM Digital builds a line of pH, EC, and TDS meters, including this COM-80 combo tester, aimed at delivering accurate water-quality readings at a price accessible to home growers and hobbyists.

Frequently Asked Questions

What does the COM-80 measure?

It measures electrical conductivity (EC) and total dissolved solids (TDS) across four selectable scales, plus water temperature displayed alongside the reading. One meter covers what would otherwise take two separate testers.

Is this meter waterproof?

It has a water-resistant housing built for testing environments around reservoirs, flood tables, pools, spas, and aquariums. It's not meant for full submersion beyond normal probe use.

How do I calibrate the COM-80?

Use the digital push-button calibration to recalibrate to any point within the meter's range rather than relying on a single fixed factory setting. The meter ships factory calibrated with a 1413 µS reference solution.

What's included with the meter?

The COM-80 ships with a protective cap and batteries installed, ready for immediate use out of the box. You won't need to source anything else separately before taking your first reading.