I purchased a whole house large filtration unit, 20" x 4.5" about 7 years ago, installed it and have used it since. The unit has a 5 micron filter first in line, and then a carbon filter after, which removes chlorine and taste, etc from the water supply. I also have reordered filters and Charcoal filters without problem from their website. It arrived very quickly , and the system functions with out problem. The larger size also prevents a pressure drop across the two filters, no flow restriction.