pH and ORP are important parameters of water quality and a wide range of process applications depend upon the ability to measure and control each. In simplest terms, both pH and ORP represent types of ion activity in liquids—pH measures hydrogen ion activity while ORP represents the potential transfer of electrons between chemicals or chemical compounds. Though measuring very different things, both pH and ORP share a close relationship and are often included together while discussing water quality. 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.

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. AA batteries: 800 hrs. battery life (included) or optional universal, 100–240 VAC (sold separately) 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. AOKI, K., NAKAO, A., ADACHI, T., MATSUI, Y. & MIYAKAWA, S. (2012). Pilot study: Effects of drinking hydrogen-rich water on muscle fatigue caused by acute exercise in elite athletes. Medical Gas Research 2, 12. Miyashita, Kazuo, et al. (2003) “Antioxidant Activity of Electrolized Sodium Chloride.” Book Food Factors in Health Promotion and Disease Prevention. P. 274-288. American Chemical Society Symposium Series, V. 851Rael, L. T., Bar-Or, R., Aumann, R. M., Slone, D. S., Mains, C. W., & Bar-Or, D. (2007). Oxidation–reduction potential and paraoxonase–arylesterase activity in trauma patients. Biochemical and biophysical research communications, 361(2), 561-565. 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. 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. 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

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? all types of water testing. The factors like pH level have a high impact on the ORP readings. If the pH of water is higher than 9.5, then ORP meters become an invalid method of water quality measurement. At a glance, an ORP electrode looks similar to a pH electrode. Like a combination pH electrode, both the sensor and the reference are housed in a common body. An ORP sensor must be chemically inert; it cannot be oxidized or reduced itself. It must also have the proper surface characteristics to promote rapid electron exchange, a property known as high exchange current density. Two noble metals have proven to work well for this purpose: pure platinum and pure gold are both used in the construction of ORP sensors. 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. 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).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"). 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. 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 AA batteries: 2,000 hrs. battery life (included) or optional universal, 100–240 VAC (sold separately) Cannon Water Technology, Inc. being water technology specialists, the company offers a wide range of ORP Meters from several brands like Sensorex, HM Digital, Myron L etc.

In addition to being used to monitor water quality in chlorinated pools, ORP meters are widely used in the food processing and water treatment industries to ensure that water is free of contaminants and safe to recycle or consume. Bottled water or tap water that is contaminant-free will have a positive ORP value. 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 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. Therefore, the answer to when to use ORP meters becomes a little complex. Although, a simplified answer to this question can be to use when the water is being treated or processed. The following are a few examples of applications where ORP meters can be used to identify water quality.

Chemicals like chlorine, bromine, and ozone are all oxidizers. It is their ability to oxidize - to "steal" electrons from other substances - that makes them good sanitizers because in altering the chemical makeup of unwanted substances, they render those substances inert. Of course, in the process of oxidizing they use up their ability to further oxidize things. The redox probe is able to measure this electromotive force for electrons to pass from the reduced species to the oxidized species. In our vitamin C example, if the concentration of the oxidized and reduced forms of ascorbic acid are the same, then we will measure an ORP voltage of -570 mV. This is according to the standard redox half-reaction: Because of the close relationship between pH and ORP, there is a scale that takes into account the ratio (mV) ORP/pH, the rH scale. The rH range varies from 0 to 42, where the extreme values represent the reducing effect of an atmosphere of pure hydrogen (rH=0) and to the oxidizing effect of an atmosphere of pure oxygen (rH=42), 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 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. The working principle of an ORP meter or redox meter is quite simple. It is a measurement of water’s capacity for electron transfer. The ORP meter consists of an electrode that is used as a probe or sensor to measure the redox potential of water. The working is similar to pH measurement. Just like the pH of a solution is measured based on hydrogen ion activity, the ORP measurement is a result of electrons’ movement inside the water. Depending on the quality of water, the In alkaline ionized water, the ORP ranges from -100 mV to – 900 mV. 7 The chemical species responsible for the negative ORP is the redox couple molecular hydrogen (H 2) and the acid ( H +) concentration. This is according to the standard redox half-reaction:This is an important part to consider regarding the molecular hydrogen concentration. Because the pH plays such a large role in the ORP, you can have one glass of ionized water with an ORP of -800 mV and another with an ORP of -400 mV, but (because of pH differences) the second glass can actually have more therapeutic molecular hydrogen than the first glass. Remember, a negative ORP is more of an indicator of the presence of H 2gas than a measure of concentration. Indeed, it’s not a measurement of concentration at all. 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 Hricova, D., Stephan, R., & Zweifel, C. (2008). Electrolyzed water and its application in the food industry. Journal of Food Protection®, 71(9), 1934-1947. User adjustable temperature compensation (up to 9.99%/°C) which also allows TC to be disabled for applications requiring non-compensated readings.