i been curious about colloidal silver myself. not much out there as far as ppm for hydro applications.and then in another set up I'm going to try some ...Colloidal shield....it's a Colloidal silver that is supposed to smother all pathogens in the water along with another systemic fungicide technically that seems like it should fix everything always have to remember to kill it systemically or else the contaminated plants will just put it back into water ...I'm also going to try and start with new plants that should not be infected