In my opinion, making your own colloidal ionic silver is better than most any commercially made CS or CIS. You can control the PPM and thus have smaller particles that are bioavailable, it is fresh, plus you can afford to make it for your family and friends. You can learn a lot like I did by reading all the older posts by Trapper, 2Tuff, Steve555 and Anunnaki and be wary of those who appear to be selling stuff. I cured a horrible sinus infection with homemade CIS, I couldn't afford to buy CIS but my generator has paid for itself who knows how many times.
No, I don't have a tester. I use a laser and watch the beam in the CIS, it will change in opacity during brewing, then make note of the time if your solution ever starts to look yellowish and stop before there. The CIS I have been making lately has a good visible laser beam (Tyndall Effect) and still clear in color. This is the best stuff. I became confused about the ionic thing when I started doing this because many spread misinformation to scare people.
Read this thread: //www.curezone.org/forums/m.asp?f=97&i=1381