We have been working to measure and understand how ion fluxes and ionic interactions regulate fundamental biological processes, and in particular promote stress tolerance in bacteria. I will present our recent work that builds on our discovery of action potentials generated within bacterial biofilms. Specifically, we showed that bacteria use potassium ion channels to orchestrate various population-level stress responses. For this talk, I will present how individual bacteria utilize magnesium flux to protect their ribosomes against antibiotics. I will propose that in contrast to the common assumption of ion homeostasis, bacteria favor a dynamic cytoplasmic “metallome” to regulate various aspects of cell physiology.