When using a Perma Pure Humidifier in Water to Gas mode, it is required that only De-ionized water be used – whether you are using an FC, MH, ME or BE Series product. The humidifiers require DI water because any cations in standard water will attract to the negative OH groups on the surface of the Nafion that act as pathways for the water and cause the membrane performance to continuously decline as the water pathways are stopped.
Additionally, we recommend that all piping and containers used for the water be plastic or another nonmetallic material as the DI water will strip the ions from the metal and deposit them on the membrane, a condition we have seen at a number of customers.