HM Digital Replacement Probe COM-300 - pH/EC/TDS/Temp Sensor - 9 x 6.2 x 5.5-in

Restore Four Nutrient Solution Readings in One Swap - 9 x 6.2 x 5.5 in

When a meter probe wears out, readings drift and nutrient adjustments become guesswork. This replacement sensor for the COM-300 meter brings back pH, conductivity (EC), TDS and temperature measurement in a single part, so you can keep monitoring your hydroponic reservoir without buying a new meter.

Sold as a single probe, it suits the home gardener who needs one spare and the commercial operation that keeps a replacement on hand for each COM-300 meter in use. Shipping weight is 0.4 lb.

Key Features & Benefits

• Four measurements, one probe — reads pH, EC, TDS and temperature.
• Glass pH sensor with reference tube — built for pH measurement in nutrient solutions.
• Stainless steel sensor pins — support the conductivity readings.
• Integrated thermometer — reports solution temperature alongside the other values.
• Storage cap with sponge — included, so you can keep the probe in storage solution between uses.

Who Should Use HM Digital Replacement Probe COM-300

Use it if you own a COM-300 meter and its readings have become inconsistent or its probe has degraded. It suits hydroponic growers at any scale who monitor nutrient solution through vegetative growth and flowering.

About HM Digital Replacement Probe COM-300

HM Digital makes handheld water-quality meters. This probe is the replacement pH/EC/TDS/TEMP sensor for the COM-300. The probe body is ABS, and the sensor uses stainless steel pins and a glass pH element with a reference tube.

Frequently Asked Questions

Q: Which meter does this probe fit?
A: It is the replacement sensor for the HM Digital COM-300 meter. Check your meter model before ordering.

Q: What does it measure?
A: It measures pH, conductivity (EC), TDS and temperature. One probe covers all four readings.

Q: When should I replace a probe?
A: Replace it when performance starts to degrade or readings become inconsistent. Calibrate first to rule out simple drift.

Q: What is TDS?
A: TDS means total dissolved solids, the amount of dissolved material in your solution. Meters typically estimate it from conductivity.

Q: How should I store the probe?
A: Put the included cap with its sponge on the probe, with storage solution in the sponge. This keeps the glass pH sensor from drying out between uses.

Q: Is the thermometer built in?
A: Yes. The probe has an integrated thermometer, so temperature is measured with the same part.