Even 50 PPM is well below the EPAs max figures for silver ingestion safety at any reasonable amount of CS water. There have been toxicity tests where scientist actually killed dogs with silver but it took about enough injected silver over a short period of time in various compounds [not even colloidal silver] to make a small bullet. They could have shot the dogs a lot faster. [They were trying to kill the dogs, not heal them. Even at that, they had to try really hard]