A cochlear implant for a cochlear stimulation system and method of assembling the implant comprising an implantable sealed housing comprising a metal feedthrough case and a metal bottom cover and containing cochlea stimulation circuitry, the feedthrough case comprising silicone enclosed feedthrough pins for connecting an electrical lead of a cochlear electrode to the stimulation circuitry, and a moisture absorbing material comprising calcium oxide secured within the housing and sufficient in quantity to absorb moisture released by the circuitry materials and leaking into the feedthrough case at leak rates of about 1×10−7 atm cc/s to maintain the cochlear implant within acceptable internal moisture limits for at least about 60 years.