This is one of the devices I use. The Bob Beck RSG-2 CS Pulser made by Scada Research. It also makes Colloidal Silver. http://tinyurl.com/f4zom
Also this one. MPG5 by Sota to target specific areas where no blood is present like the lymph system, or organs where critters, or other pathogens might be hiding. http://tinyurl.com/koeft
Not suggesting that these are better than others because I haven't used others.
I also have the Hulda Clark type zapper that you already have.