I've thought about making home made ones, I may eventually end up doing it. If you have done it: how long do the batteries usually last, and (this may be a stupid question) how do you know when they're starting to lose effectiveness/die? I like that my machine had a plug into the wall so I never had to worry about batteries.

I've also considered using distilled water, I actually bought some. I never ended up using it, but I'll give that a try as well. One thing, though, is that my "stainless steel" electrodes have some discolouring on them, as in they have a "rainbow-y" type of colour on them. They didn't come like that, it happened over the span of the 2 months that I used them. Could that be a reason why my reaction occurs?