Replied by Art (California ) on 01/30/2018
In reply to Michael in Seattle,
There are several ways you can end up with black particles at the bottom of your ionic silver or colloidal silver. One way is if you are running too high of a current on your cell during production. To resolve this problem, you will need to lower your current setting until no black particles are present at the end of the run or you will have to use a magnetic stirrer or both. A larger anode such as a 1 ounce silver bar which is more efficient than a rod or a wire can help resolve this problem also. I only use silver bars for my anode because they are more efficient and then I use a thinner copper wire (#14) for my cathode to help reduce plateout onto the cathode.
If the issue is not current that is too high, it may be plateout from the cathode that has fallen off the cathode into the cell either during production or when removing the cathode from its holder.
Another way that this can happen is if you cook your batch beyond 35 parts per million (PPM) without using a stabilizer of some sort such as a capping agent. After 35 ppm the silver can start to agglomerate and form larger particles until the particles get so large that they fall out of suspension and this will also be noticeable as black specks at the bottom of your cell. This means the silver is going to be weaker than what you had calculated for and it is not going to be as effective at neutralizing pathogens because the particle size will likely be too large.
Not knowing how you are making your silver, it is hard to say what the exact cause is.
Art
