I have the silver puppy and love it. I also test with a flashlight beam or laser beam. The beam shot through the middle of a clear glass of water is hard to see but through "clear" silver solution in a clear glass or beaker shows the beam very distinctly. The light is hitting very small particles of silver. It is like shining a flash light beam through a smoky room at night with the lights off. I/ve made maybe 20 gallons of silver so far and see very little change in the silver rods but hey they only cost $10 anyway. I also tend to believe that fresh is best so homemade is king. After reading a whole bunch came to the conclusion soverign silver was best but now think differently. I think the fresh homemade is best. Takes quite a while to make a batch from distilled water so I really like the set it and forget (automatic shut off) feature of the silver puppy as once it starts developing ions at the right dose (15 ppm) the conductivity is high and it can "run away" if not stopped in a very short time. So you have to moniter it. Also you can't tell the density (ppm) unless you have an expensive tester whereas the silverpuppy will shut off and you know its 12-18ppm.