If you are interested in building your own generator, I just finished a really nice unit that has many of the features of the professional generators - constant current ( adjustable ), magnetic stirrer, laser mount, etc...
I designed it for my mother-in-law who was going to use 3-9v batteries, however it seemed like a great opportunity for a new project I could share online with anyone who is interested in making something similar.
You can download all the files needed to build the project at my blog here:
I also put together a nice youtube video of the first prototype being built ( which I sent out to my mother-in-law ) here:
The device produced 15ppm of colloidal silver in 5 hours. The solution was very clear indicating that the particles were quite small - you can see the laser beam test toward the end of the video, or the photos on the blog link above.
Any comments / feedback is more than welcome.