You have to remember from your training though that regardless of what they are breathing into thier lungs at the surface, impurities in your air during a dive are magnified by the pressure the diver is experiencing. A small amount of something in the air you are breathing right now at your computer might not bother you but in 66 feet of water could actually make you very ill if not kill you! The carbon filter will remove many of those impurities. And while this is not a common occurance today, I have first hand knowledge of a diver using the Bio Filter being the only diver on a Live Aboard not to ge sick when the boat's compressor was suddenly found to be putting out bad air.
Edited by BobG (01/19/08 05:08 PM)