Clearwater Enviro Technologies Inc., of Clearwater, Fla., manufactures several ionization systems including the “Enterprise,” a digitally controlled unit that releases precise amounts of copper and silver ions into the water. The copper ions kill algae, while the silver ions kill bacteria and viruses. This will allow swimming pool and hot tub owners to lower chlorine use by 90 percent or more. The units can handle any amount of water from hot tubs to 2.4 million-gallon pools.