---
product_id: 263621373
title: "OPR Meter, ORP Redox Meter Tester -1999~1999mV Oxidation Reduction Potential Tester with 256mV ORP Calibration Buffer for Water Testing, Aquarium, Research Laboratory"
brand: "gain express"
price: "€ 38.87"
currency: EUR
in_stock: true
url: https://www.desertcart.ie/products/263621373-opr-meter-orp-redox-meter-tester-1999-1999mv-oxidation-reduction
store_origin: IE
region: Ireland
---

# Accuracy: 1 mV steps Calibration: 256mV buffer Range: -1999 to 1999 mV OPR Meter, ORP Redox Meter Tester -1999~1999mV Oxidation Reduction Potential Tester with 256mV ORP Calibration Buffer for Water Testing, Aquarium, Research Laboratory

**Brand:** gain express
**Price:** € 38.87
**Availability:** ✅ In Stock

## Summary

> 💡 Unlock the Secrets of Your Water Quality!

## Quick Answers

- **What is this?** OPR Meter, ORP Redox Meter Tester -1999~1999mV Oxidation Reduction Potential Tester with 256mV ORP Calibration Buffer for Water Testing, Aquarium, Research Laboratory by gain express
- **How much does it cost?** € 38.87 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.ie](https://www.desertcart.ie/products/263621373-opr-meter-orp-redox-meter-tester-1999-1999mv-oxidation-reduction)

## Best For

- gain express enthusiasts

## Why This Product

- Trusted gain express brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Portable Design:** Compact and lightweight, take it anywhere for on-the-go testing.
- • **Versatile Water Testing:** Ideal for aquariums, pools, and laboratories—know your water quality in minutes!
- • **User-Friendly Calibration:** Effortless 1-point calibration ensures reliable results every time.
- • **Precision at Your Fingertips:** Experience unparalleled accuracy with 1 mV measurement steps.
- • **Essential for Health-Conscious Consumers:** Stay informed about your drinking water quality and filtration efficiency.

## Overview

The ORP Redox Meter is a highly accurate and portable device designed for measuring oxidation reduction potential in various water sources. With a measurement range of -1999 to 1999 mV and 1 mV step accuracy, it is perfect for testing drinking water, aquariums, and more. The device features a user-friendly 1-point calibration process and comes with a 256mV calibration buffer, making it an essential tool for both professionals and health-conscious individuals.

## Description

OPR Meter, ORP Redox Meter Tester -1999~1999mV Oxidation Reduction Potential Tester with 256mV ORP Calibration Buffer for Water Testing, Aquarium, Research Laboratory

## Features

- Inexpensive and practical device with 1 point calibration, easy to use and highly accurate
- Scale of measurement: -1999 ~ 1999 mV in 1 mV steps
- Find out quickly the sort of water you drink and how your filter works efficiently and effectively.
- Determine the water quality indicators with this ORP meter in just a few minutes. Carry-everywhere design.
- Best for laboratory and industrial households (drinking water test, in aquariums, artificial ponds, wastewater), pools, water treatment systems, aquaculture, spa, etc.

## Product Details

- **Brand:** Gain Express
- **Power Source:** Battery Powered
- **Color:** ORP Meter + Calibration Powder
- **Item Weight:** 60 Grams
- **Min. Operating Voltage:** 1.5 Volts

## Images

![OPR Meter, ORP Redox Meter Tester -1999~1999mV Oxidation Reduction Potential Tester with 256mV ORP Calibration Buffer for Water Testing, Aquarium, Research Laboratory - Image 1](https://m.media-amazon.com/images/I/71rG-rHlVCL.jpg)

## Questions & Answers

**Q: I know how to adjust the calibration but you need a standard to assure its set correctly. What do i do?**
A: You may buy the ORP calibration solution for our store, the following is the link, or you may buy the calibration solution from other sellers, you may use 225mV, 256mV or 400mV solution to calibrate your meter. 

https://www.amazon.com/calibration-solution-Oxidation-Reduction-Potential/dp/B01FS0G8WK/ref=sr_1_fkmr0_1?keywords=ORP+256mv+standard+solution&qid=1558509756&s=gateway&sr=8-1-fkmr0.

**Q: What’s the difference between this one which is green and the other one which is red? Is one newer than the other?**
A: The Green one is new design with same function of red one(ORP-002).

**Q: Will this work to show the ionization - orp of my invigorated water purifier?**
A: It will show the ORP rating of the water. However, Reduction Potential in water, without adding a supplement comes from splitting apart water molecules with electrolysis, creating negative ionized hydrogen.
 Oxidation is electron loss. Reduction is electron gain. A standard filter should not affect the ORP very much.. 
I dont know much about invigorated filter, but alkaline does not necessarily mean reductive.

**Q: Does this measure free chlorine levels?**
A: Hi,it can only measures the oxidation-reduction potential (ORP) value of water, cannot measure free chlorine levels.

## Frequently Bought Together

- ORP Redox Meter -1999~1999mV Oxidation Reduction Potential Tester with 256mV ORP Calibration Buffer for Water Testing, Aquarium, Research Laboratory
- PH Meter for Water Hydroponics Digital PH Tester Pen 0.01 High Accuracy Pocket Size with 0-14 PH Measurement Range for Household Drinking, Pool and Aquarium

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*Product available on Desertcart Ireland*
*Store origin: IE*
*Last updated: 2026-03-09*