I live in the desert with fairly dry air most of the time. We are in the monsoon season as they call it right now and I am seeing a bit more water come out of the drain tube every time I release the pressure in the hose once the bottle is full, so it is definitely working and extracting more moisture with the higher humidity. Do I need something else with the GX CS3 to further reduce moisture in the air output? I don't want to ruin my PCP guns. Is there some way to check the moisture content of the air coming out of the compressor?
As you said above, you live in the desert (Arizona?), so even when the "monsoon" season comes, your humidity is so much lower than where I live (North Alabama) that I would not sweat about it AT ALL!
The only caveat is if you insist on shooting the bottle down so low that you really have to either do one LOOONG session or (the reasonable way) pump it back up with breaks to keep the pump (compressor/hand pump/whatever) from getting hot and allow it to be able to cool down quickly.
Where I live, the dew point has been 75 for most of the summer and the RH has been at least 50 and often 80-100%. I seriously doubt you ever see anything even close to that.
When I pump (hand pump) up my airguns, I always do it indoors (a/c) and I have hygrometers (because I love cigars) that let me know how dry the air is at any moment.
Does this keep out ALL moisture? No, of course not. But in 4 years I have never had a problem with moisture in any airgun.
If you are using a "compressor" and only filling a bottle/pressure tube when it gets too low to shoot reliably, then you may/
will have moisture issues.
Compressors are great, but just like hand pumps, if you run them too long in a single session (increased heat and moisture)... you will have more problems.
JMHO-YMMV