Maximum Yield USA 2015 April | Page 110

the power of orp Oxidation reduction potential (ORP) is one of the most overlooked factors influencing crop management in hydroponics. Terms such as pH, TDS and EC are comparable acronyms that are ubiquitous within the industry, with countless products available to monitor and influence their levels. But what exactly is ORP? And how can you use it to your advantage in simple, yet effective, ways? Oxidation and Reduction First, let’s get a clear understanding of what exactly oxidation is. Simply put, it is a process by which an oxidizing agent adds oxygen to a solution and changes it. Chemically speaking, oxidation occurs when electrons are lost due to a reaction. Because electrons have a negative charge, the use of powerful oxidizers results in a solution with a more positive charge. A common example of this is corrosion. When an iron nail, for instance, is exposed to oxygen and moisture, iron oxide, or rust, is created and the iron nail is considered to be oxidized. The oxidizing agent in this reaction is oxygen. There are many different oxidizers out there, varying broadly in strength. If an oxidizer is strong enough, it will dissolve some or all of the components in the solution, especially organic compounds. 108 Maximum Yield USA  |  April 2015 “While oxidizers add oxygen to other substances, there are reducing agents that remove oxygen from substances, making the solution more negatively charged by adding electrons.”