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

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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 advanced four-electrode cell for conductivity/resistivity/TDS eliminates polarization, allowing greater accuracy and stability with minimal maintenance.

AA batteries: 2,000 hrs. battery life (included) or optional universal, 100–240 VAC (sold separately) When an oxidizing and/or reducing agent is dissolved into an aqueous sample, they may react with materials present and produce a voltage, or electromotive force (EMF), that is related to the ratio of oxidized to reduce species in the sample. An electron exchange can develop between this solution and an inert metal sensor immersed in the solution, and the voltage can be measured (when compared to a reference electrode) with a pH/mV meter. This type of measurement is known as redox or ORP. The units of measurement are in mV. Another common misconception is trying to relate ORP to cellular voltage. 14Some have claimed that because cells have a negative voltage, drinking negative ORP water is healthy. 14However, these two voltages are very distinct from each other and do not relate under biological conditions. Cells have their voltage due to differences in ion gradients and carboxylate moieties from proteins and fatty acids. 15Oxidation-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?

AA batteries: 800 hrs. battery life (included) or optional universal, 100–240 VAC (sold separately) Measures - pH, ORP, free chlorine and conductivity (and resistivity and TDS) - please see product attachments for full measuring ranges. 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. 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.Basically *you have different chemical species in the water that can either undergo oxidation or reduction; these form “redox couples”. 3For example, adding ascorbic acid (vitamin C) to water gives a negative ORP 4based on the ratio of reduced ascorbic (HA) acid to oxidized ascorbic acid (DHA) according to the Nernst equation. 5

An ORP system does not have a high impedance source (like a pH bulb), but is a potentiometric device that produces a voltage. It also uses similar cables, connectors, and calibration solutions. For this reason, a high impedance electronic meter (pH) with many user-friendly features are a benefit for this measurement. You can make the ORP negative by decreasing the H +concentration (raising the pH) and/or increasing the dissolved molecular hydrogen concentration. Conversely, you can make the ORP positive by increasing the H +concentration (lowering the pH) and/or decreasing the dissolved molecular hydrogen concentration. Important Considerations 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 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. 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.