Aquios FS-220 Salt Free Water Softener and Filtration System, Blue Perfect solution to both filter and soften water Utilizes a carbon block filtration rated at 5 microns Non-salt, food grade additive that softens hard water and, over time, eliminates existing scale build-up Great tasting water, no chlorine aftertaste, conditioned water. Port size 3/4inch threaded brass Economical and space-saving solution. Operating Temperature: 40 to 115 degrees Fahrenheit