MW500 OPR Meter


The MW500 PRO ORP meter is one of the most popular meters with its reliable, fast and simple operation as well as its accuracy.

The ORP Meter is preferred by people looking to dial in their testing program when they have an ongoing need to maintain levels. Common uses are aquariums, swimming pools and spas, and other water quality monitoring uses.

The ORP meter can also be used to measure sulfur dioxide in wine using the manual Ripper titration method.

The ORP meter offers:


The ORP meter is accurate to ±5 mV exceeding the needs of most users.

Low maintenance

The ORP Meter comes with SE300 ORP probe that is both low maintenance (gel filled) and able to withstand more challenging samples (double junction).


  • Fast easy to read current results with large digital LCD readout
  • Accurate to ±5 mV
  • Gel-filled, double junction lab grade Platinum ORP electrode for low maintenance and high performance
  • 3 feet probe cable for extra flexibility when testing
  • Auto shut off and low power demand for a 300 hour extended battery life (battery included)

Use and Care 

Properly maintaining your ORP probe will give you fast, accurate results for longer.

Here are our top three tips.

1. Always store with the cap full of buffer or storage solution, not water.

2. Clean your probe regularly by soaking in cleaning solution.

3. Check the probe using solution to ensure the probe is good.

Technical Specifications

mV Range: ±1000 mV

mV Resolution: 1 mV

mV Accuracy: ±5 mV

ORP Electrode: SE300 (included)

Environment: 0 to 50°C / 32 to 122°F; max RH 95%

Battery Type: 1 x 9V (included)

Battery Life: Approx. 300 hours of continuous use

Dimensions: 5.7 x 3.1 x 1.6 inches

Weight: 7.8 ounces (with battery)

Contact us

If you have any questions or require further information, please do not hesitate to email us at [email protected], call us on +44 (0)113 286 4536 or submit a contact form.