I have purchased a bottle of 40ppm clear "colloidal silver" some months ago, and today for curiosity i have reduced it.
Used 50% karo solution, about 10 drops for 100ml of liquid (in case it have more ppm than expected), and after about 20 minutes, it turns out a very strange color.
Maybe its too agglomerated? Or it can be other particles than silver?
Also compared it with 40ppm that i have made.