LUBOLD8431 once bubbled...
You can keep buying filters... The average diver breathes more CO2 ppm in the air outside than in their cylinders.
in most cases Thats not true.. the commmon checmicals used for filtration for all practical purposes don't remove co2. if your intake to your compressor is indoors the intake can be as high as 2500 ppm. probably moe like 400-800ppm, outdoor supplies will probably be in the range of 200-400ppm, unless you are using an oilfree compressor the compressor will ADD some co2, it should be small though on a properly operating compressor.. if you want to getrid of the co2 you have to use a chemical like rb divers use..
I don't have to change filter media that often.. I put out a larger initial investment and bought a RIX oilfree compressor (with all 4 stages liquid cooled).. in the long run its cheaper plus supplies better gas..
at shallow depths co2 isn't an issue but as depth and po2 increases it has to be considered.
The only filtration I put after my banks is micron filters to make sure no particulate matter is introduced into the gas stream.
also for the filtration to work best the filter bed must be kept under pressure and I have seen way to may systems without back pressure regulators to keep the media under full pressure..
if filtration is done after the banks it is possible for moisture to get trapped in the filter media reducing its effectiveness not to mention potential channeling on some systems..
there are some real advantages of back pressure regs, but in the secondary filtration case probably unrealistic..
a good coalessor (sp) to remove moisture and a back pressur reg after the filtration will generally extend the life of the filter media.
The other reason I believe all gas should be as clean as possible, unless you have 2 seperate gas paths and fill whips, you are adding contaminates to your equipment which is cumulative.
just my 2 cents
