What is the difference between the Ceradyn and the Gravidyn?

The Ceradyn is a ceramic-only water filter that will remove not only sediment/debris from your water, but microorganisms like protozoa and bacteria down to .2 microns. The ceramic elements will last for approximately 39,000 gallons depending on your water quality.

The Gravidyn has the same ceramic with the addition of carbon in the core of the elements. Once activated with water, you have 6 months before you need to replace the Gravidyn elements due to the shelf-life of activated carbon. The carbon in the Gravidyn helps with taste, odor, and some chemical reduction.