Microban does not kill bacteria, Microban is purely used as an inhibitor that does not allow bacteria to leach to a surface. If the water is properly balanced and sanitized there should be no bacteria in the pool or spa to leach onto a filter surface in the first place. Also having a Microban media will not prevent bacteria from leaching to other surfaces and components of the pool or spa if the water is not properly balanced it will simply not allow them to leach to the filter media.