Water Filtration System, Filters, Cartridges: Halo Water Systems are maintenance free whole house water filtration and conditioning systems. New under sink reverse osmosis (RO) systems now available. For city water, well water, residential & commercial solutions. 10 year warranty. H5-H100 HALO 5 Stage 1 Whole House system, HG-RC-75 and more. HG-75 Halo Guardian Tankless Filter And Scale Inhibitor System Filter.