I've never used kangen water, but it is basically ionized water with a little alkalinity. I looked at water ionizers because they were being touted as a safe and effective cleaning agent. An alternative to bleach in restaurant sanitizing systems.
Does it work? As a sanitizing agent, yes. BUT, you can achieve exactly the same thing by adding a small amount of bleach and citric acid to regular water. Restaurants, hospitals, and other institutions use it because it is easier to handle. They don't need to be trucking in and storing large drums of bleach, which is a hazmat agent, and mixing it onsite.
The ionizing units themselves are expensive. Even a small one can run you $2k.
But for the purposes we want to use it for it is impractical. From an oxidizing and disenfecting standpoint, all you need to do is add just enough bleach that you can neither smell nor taste it, add some citric acid, and use it.
Same effect as paying $40/gallon for fancy pants water.
Easy enough to google if you don't believe me.
Now, will it work on active PM? Does anything?
It will likely work as a good preventative as one step in your ipm arsenal. Plants shouldn't be bothered by it, but be careful to keep it out of the soil and off the roots.
But despite what some internet hacks/dudes claim, it isn't a magic bullet.
Just one opinion of course.
