HM Digital ORP-200 Waterproof Professional Series Handheld Meter, White/Green, ORP

Product Information

pH meters generally consist of a glass electrode connected to an electronic meter that measures and displays the pH reading. Meters can range from units that combine all the parts into a simple, handheld unit or more complex, laboratory-quality instruments that provide highly accurate readings and a host of other functions. You may have heard of ORP, but what does it mean and what role does it play in water-quality testing? We’ve laid out the basics of ORP to help you get up to speed. Tyler LeBaron. (2013 ) “Changes in Oxidation-Reduction Potential of Aqueous Solutions as a Function of pH and Hydrogen Gas Concentration” The Journal of Kitchen Chemistry 2013. 1. P.12 OSTOJI?, S. M., STOJANOVI?, M. D., CALLEJA-GONZALEZ, J., OBRENOVI?, M. D., VELJOVI?, D., ME?EDOVI?, B., KANOSTREVAC, K., STOJANOVI?, M. & VUKOMANOVI?, B. (2011). Drinks with alkaline negative oxidative reduction potential improve exercise performance in physically active men and women: Double-blind, randomized, placebo-controlled, cross-over trial of efficacy and safety. Serbian journal of sports sciences 5, 83-89. SHIRAHATA, S. A. N. E. T. A. K. A. (2002). Reduced water for prevention of diseases. Animal Cell Technology: Basic and Applied Aspects 12, 25-30.

All glass electrodes have a bulb which must be kept hydrated and a reference junction which must be kept wet to prevent excess leakage of the internal electrolyte solution from the reference junction. It is recommended keeping the electrodes in a storage solution between uses. Special cleaning solutions are also available to ensure electrodes are free from contamination or build-up which can affect performance and shorten the lifespan of the electrode. The electrolyte within some reference electrodes must also be refilled periodically. Other electrodes are gel-filled or "low-maintenance" and do not require refilling. ORP electrode acts as an electron donor or acceptor. If the contaminants in water are reductant, then the ORP electrode acts as an acceptor. If the contaminants are being oxidized then the ORP electrode acts as a donor. During this electron transfer, the potential difference is generated owing to the electromotive force. This potential difference is measured by the Aqua-logger or Aqua-meter to give a reading according to the ORP scale. Therefore, ORP meters are also known as differential ORP probes. ORP is quite a popular term in water quality measurement. ORP is an acronym for Oxygen Reduction Potential. It is also recognized as the redox potential of water. What exactly does ORP mean? It is a measure of how oxidizing or aerated the water is. Higher the ORP, the higher is the oxygen level in the water. This means ORP is basically merit of cleanliness and healthiness of the water. Owing to this ORP is such an important term in water quality measurement. The ORP meters are utilized to measure the quality of water. Some common applications of these ORP meters are water disinfection units, industrial water processing plants, drinking water supply centers, etc. If you intend to know more about ORP meters, what they are, how do they work and when to use them, then this post is for you. This post discusses answers to all these questions.These important points underscore the importance of actually measuring the molecular hydrogen concentration and making comparisons between hydrogen-water devices based off H 2concentrations, as opposed to pH and ORP alone. ORP Misconceptions

If a substance doesn’t have enough electrons, it will actively attempt to acquire them through the process of oxidation—a chemical reaction in which one agent is oxidized (i.e., loses electrons to another agent). Because substances with positive ORP readings are looking to acquire electrons, they are considered oxidizing agents. An ORP sensor consists of an measuring electrode, a reference electrode, and some sort of display, in much the same fashion as pH measurement. An ORP meter is really a millivolt meter, measuring the voltage across a circuit formed by the reference electrode and the measuring electrode.Automatic or manual temperature compensation - pH sensors incorporate a built-in temperature sensor.

Oxidation-reduction potentialcan be measured using a potentiometer (voltmeter) or an ORP meter. 1 Water produced from electrolysis (ionized water), as well as other forms of hydrogen water, exhibit a negative ORP. 2 But what is the meter actually measuring? And how does it work? pH stands for "potential of hydrogen" and is a measure of hydrogen ion concentration. A high concentration of hydrogen ions results in acidity while a low concentration results in alkalinity. The concentration of hydrogen ions is represented on a scale from 0 to 14 with 7 being neutral (i.e. an equal number of hydrogen (+) ions and hydroxide (-) ions to cancel each other out). Values below pH 7 are acidic and values above pH 7 are alkaline. The scale is logarithmic, meaning each full point increases or decreases by a factor of 10x. Some extreme substances can score lower than 0 or greater than 14, but most fall within the scale. User adjustable temperature compensation (up to 9.99%/°C) which also allows TC to be disabled for applications requiring non-compensated readings. The HI-98190 combines all of the features of a benchtop into a portable IP67 rated waterproof enclosure making them one of the most versatile meters on the market.Oxidation reduction potential, or ORP, is a measure of a substance’s ability to either oxidize or reduce another substance. It is measured by the electrodes of an ORP meter. A positive reading on an ORP meter means that the substance is an oxidizing agent; a negative reading indicates that the substance is a reducing agent.

The platinum sensor is often preferred because it is mechanically simpler and safer to produce. Platinum can be welded to glass and has the same thermal coefficient. Sensors made of gold cannot be welded to the glass and are often placed in plastic supports applied to the glass or plastic tube by means of tiny elastomeric bungs. The gold or platinum sensor signal is carried through the electrode body, and together with the reference signal is conducted to the measurement meter via a coaxial cable with BNC connector. ORP is unaffected by temperature but readings will vary as the pH fluctuates. As the pH goes up, the millivolt reading on an ORP meter will go down. This can greatly affect the effectiveness of sanitizers such as chlorine, which is by far the most commonly used chemical for water sanitation. For example, at a pH 6.0, 96.5% of the Free Available Chlorine in the water is in the active killing form, while at pH 8.5, only 10% is in that form. Bringing the pH down or adding more sanitizer will raise the millivolt reading. While for most applications ORP measurement is concerned with oxidizers for their sanitizing effect, there has been increasing interest with reducers. Free radicals are atoms and/or molecules with an unpaired electron. Introduced to our bodies as byproducts of biochemical reactions and from the air we breathe and food we eat, free radicals are unstable and desire balance so they try pull electrons (oxidize) from wherever they can. In acquiring balance for itself, the free radical damages other biological molecules in the body. Reducers, also known as antioxidants, donate the electrons sought by free radicals thus minimizing the degenerative effects of free radicals on the body.Some have falsely taught that adding minerals to the water gives a negative ORP, but it’s not an antioxidant ORP. Adding mineral salts (e.g. magnesium chloride or calcium carbonate) alone will not give a negative ORP as that is not a redox couple that can readily undergo an electron transfer. 11 However, addition of magnesium metal to water obviously does produce a negative ORP 12due to the production of therapeutic molecular hydrogen 13 ( as explained before). Another important point is that once the water is at a pH around 9.5 the ORP meter is virtually an invalid method to compare any solutions H 2concentration. 8Possibly because at these higher pHs the H +ion concentration is very low (1 X 10 -10M) and may be near the the detection limit of an ORP meter resulting in spurious readings. 8MHF has measured some waters with equal pH and ORP, but one has a concentration four times as great as the other one. This can make a significant difference in the therapeutic value of the water. Kotz, John C., Paul M. Treichel, and John R. Townsend. Chemistry & chemical reactivity. Cengage Learning, 2011. ORP calibration with the ultrameter is not necessary. Due to the hazardous nature of ORP chemical standards, the ultrameter features an inbuilt electrical calibration. Frequency: Never.