What is oxidation reduction potential?
Oxidation reduction potential or ORP is measurement for water.  A millivolt meter can measure ORP and it is a measure of the potential of water to carry or hold antioxidants.  It is not a guarantee of antioxidants in water.  One form of antioxidants in water is free floating dissolved hydrogen.  A good analogy of antioxidants in water is the following: ORP is like a big swimming pool of potential but at the moment its currently empty and dissolved hydrogen is like ball of finite size.  The larger the ORP 'swimming pool' the more dissolved hydrogen 'balls' can fit in that pool.  An ORP with a large negative value is huge swimming pool, and an OPR with a high positive value is no swimming pool.  ORP can also measure whether water is acidic or alkaline.  ORP that is negative tends more toward alkaline water, and ORP which is positive tends more towards neutral water and acidic water.