My opinion of the Silvertron generator is that it uses some fancy touch screen controls and a lot of hype to charge a premium price, and, while it may be able to more precisely measure the PPM, it does NOT produce a solution that produces mostly true Colloidal Silver - and I note that they state that higher PPM " Colloidal Silver " can be produced by adding "certain food items available in most grocery stores". What they are likely referring to is some form of protein, which suspends the ionic particles so that they can falsely call it " Colloidal Silver ". It isn't. It is ionic silver suspended by protein - and that is not something I would recommend at all. A solution that is mostly true colloidal silver can NOT be produced with a 9 volt generator - it takes much, much higher voltage to produce mostly colloidal silver.