RH is the best measure of the healthiness of that ionized water. I always consider the rH to be the most important measure to look at in any water ionizer comparison test.

• Here’s an example to help you see why the rH formula is necessary: if you have two water ionizers both producing water at a pH of 9.5, and one has an ORP of -300 and the other has an ORP of -400, then it would be easy to see that the one with -400 is producing water at a healthier overall quality. However, most people testing water ionizers don’t get the exact same pH readings for all the water ionizers tested. So the rH formula is necessary to really see which water ionizer is producing the healthier water. The formula is a very simple one, and anyone comparing water ionizers should look at the rH of the water at the drinking water levels if they are trying to figure out which water ionizer is best. Because ORP is a very tricky measure to get and ORP meters can vary from test to test [depending on how well or frequently they're cleaned, source water and other factors] it’s important to only compare the ORP or rH of water ionizers tested in one setting by the same tester. RH is measured on a scale of 0 to 42, with 0 being the healthiest and 42 the unhealthiest. Tap water in St. Louis is usually around 30 - 35 rH. Any water under 28 rH is considered “reducing” and so is healthy for you.
• “The relative hydrogen scale was first proposed by Clark in 1923 to the scientific community (mostly inorganic chemists) as a means of measuring the true reducing power of hydrogen present in an aqueous solution…”* It is mostly used in water treatment facilities, but I imagine that the water ionizer engineers use it to test their own water ionizer designs. Go to this website to see this article and get a more thorough and scientific explanation of rH: http://h-minus-ion.vpinf.com/rH-score-1.html

• I stumbled upon this when I was debunking the Hydrogen Stick as a supposed solution to the health issues solved with a water ionizer. The Hydrogen Stick people were proporting that Dr. Hayashi believes Hydrogen [H-] has caused greater health benefits than alkalinity. They were saying that the Hydrogen left the ionized water through evaporation very quickly and so within an hour or there-abouts you'd be without the H- benefit if you used ionized water ...and they were claiming that the Hydrogen stick provided more Hydrogen and thus greater health benefits than ionized water. I wanted to test this, so in searching for a way to actually measure the Hydrogen in the water, I found that the way to find the Hydrogen [short of having a $10,000.00 meter] was to use the rH formula and scale to compare two solutions to each-other. The rH scale goes from 0 to 42 and the solution which has an rH closer to 0 is healthier than the other. I then was able to test the Hydrogen Stick water against ionized water. The results were that ionized water had a far better rH [relative Hydrogen] than the Hydrogen Stick, and even after a day of soaking a Hydrogen Stick and ionized water sitting for a day...the ionized water was far better. The Waterman ionizer pitcher [H2go] works on a similar basis as the Hydrogen Stick [except it also filters the water] and it gets a better rH than the Hydrogen Stick. But out of all of these a water ionizer is so much better -- there really is no contest.