I've used the Silvonic Automatic CS generator from Elixa.com for several years. I think it has the same electronics as the Silver Puppy and produces clear solutions that really work. Elixa even has a model that makes a gallon in about 6 hours with a stirrer. They even have a lifetime warrantee.
They cite some recent research from Rice University that shows ions doing the killing.
When you make it yourself, you can drink lots of it for very little $.