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. Now that it discussed where and when one can use the ORP meters, then let us take forward to how ORP Meter works. 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. Free chlorine is not measured directly, rather calculated using ORP, pH and temperature measurements. Frequency - Every 2 weeks (pH).

Automatic or manual temperature compensation - pH sensors incorporate a built-in temperature sensor. Kotz, John C., Paul M. Treichel, and John R. Townsend. Chemistry & chemical reactivity. Cengage Learning, 2011. pH calibration on the meter is performed at either two or three points. You should calibrate with pH 7 buffer first then followed by either pH 4 and/or pH 10 buffers. The recommended frequency of calibration of pH is every 2 weeks. GONCHARUK, V. V., BAGRII, V. A., MEL’NIK, L. A., CHEBOTAREVA, R. D. & BASHTAN, S. Y. (2010). The use of redox potential in water treatment processes. Journal of Water Chemistry and Technology 32, 1-9. 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.

What is an ORP meter?

As with pH meters, regularly cleaning and properly storing ORP electrodes is important in ensuring accurate results. ORP meter, however, do not require calibration. ORP stands for oxidation reduction potential. It is a term that is usually found in the water treatment and food processing industry. ORP meters measure the cleanliness of the water and how it can break down contaminants. They work by measuring dissolved oxygen in the water. If there are more contaminants, there will be less dissolved oxygen as the contaminants will use up the oxygen particles, thus resulting in a lower ORP level. Now that the introduction, working, and applications of ORP probes are discussed, it is essential to know that the quality of the ORP meter also impacts the results. Therefore, one must buy from trusted suppliers like The ORP electrodes are designed to 0mV reading that is null reading at 7pH. As the pH value deflects over or below 7, the deflection in ORP is seen. The extreme range of ORP meter reading remains between -1500mV to1500mV.

User adjustable temperature compensation (up to 9.99%/°C) which also allows TC to be disabled for applications requiring non-compensated readings. 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. AA batteries: 2,000 hrs. battery life (included) or optional universal, 100–240 VAC (sold separately)For more information about how to interpret ORP readings and use ORP meters, research your chosen ORP meters and its unique features. When it comes to swimming pools, ORP levels can usually be adjusted by adding more active chlorine to the water to boost its antioxidizing potential. More sophisticated water purification systems may involve a more complex balancing of total dissolved solids (TDS) in water to achieve a more favorable oxidation reduction potential. pH measurements are important in medicine, biology, chemistry, agriculture, forestry, food science, environmental science, oceanography, civil engineering, chemical engineering, nutrition, water treatment & water purification, and many other applications.

Alternatively, a consultation visit from one of our highly experienced product specialists is available for this range. Typically our specialist will be able to go through the following aspects with you to help you make the right choices and be able to deliver them on time and and on budget. up to five-point calibration, seven standard buffers available (1.68, 4.01, 6.86, 7.01, 9.18, 10.01, 12.45) and five custom buffers 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. 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.ORP measurement is important for many applications such as drinking water, swimming pools and spas maintenance, cooling tower disinfection, groundwater remediation, bleaching, cyanide destruction, chrome reductions, metal etching, fruit and vegetable disinfection and de-chlorination. ORP is also the only practical method we have to electronically monitor sanitizer effectiveness. Hricova, D., Stephan, R., & Zweifel, C. (2008). Electrolyzed water and its application in the food industry. Journal of Food Protection®, 71(9), 1934-1947. On the other hand, electrons that have a surplus of ions can afford to lose ions to oxidizing agents without becoming destabilized themselves. For this reason, they are referred to as antioxidizing agents, or reducing agents. The higher or lower an ORP reading (positive or negative), the more oxidizing or antioxidizing a substance is, respectively. The fact that molecular hydrogen is the therapeutic ingredient in ionized water eluded scientist for decades. 9It is no wonder that misconceptions of ORP have been promulgated over the years. Some have suggested that the reading is due to free electrons, actual physical charges on water molecules, charged or ionic minerals, 10and virtually everything else except for molecular hydrogen.

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 The ORP meters are used when the water quality in terms of sanitization or contamination is to be measured. The ORP meter measures redox potential by measuring the electromotive force of the electron taken to pass it from reduced species to the oxidized species. These ORP meters cannot be used for 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. Similar to the manner in which acidic or alkaline solutions are quantified by pH measurements, solutions can also be graded as oxidizing or reducing based on measurements of ORP (oxidation reduction potential often called "redox"). Accuracy of pH measurements is dependent upon well maintained and properly calibrated instruments. The main factors that degrade the performance of an electrode are coating, contamination and aging. Necessary maintenance and calibration depends on these factors and, of course, of the accuracy required from measurements.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.