We all need to do something to help our PCPs avoid damage from moisture. Alan's linked piece explains using real data that high pressure air looses it's ability to hold the moisture that is in the air at it's normal 1 bar pressure. If the high pressure air is hot enough, however, it can still hold a significant amount of moisture. But it won't stay that hot and when it cools the moisture will come out. So if you use a compressor, the air it puts out is likely to have moisture you do not want in your gun. With a hand pump, if you pump in short sessions and bleed often, maybe not. Even then I would want at least a small absorbent filter. It seems best to use a little more than you think you really need. If you use a compressor to fill your gun directly, you definitely want a decent filter. At least for the lower priced pumps like the YH I use, that means adding some sort of filter. I like to use one with color change dessicant in it so I can see when it gets wet. If you use your pump to fill your SCBA tank, like I do, the moisture would not go directly to your gun, it would go into your tank. It could damage the aluminum liner causing the tank to be damaged. It might also come out with the air and go into your gun. Filling a SCBA tank requires a longer compressor run which is likely to be higher in temperature meaning more water to condense out so we have to deal with it.
Regardless of your fill method and your steps to address moisture you want to monitor how it is doing. I pull the absorbent filter from the filter housing the YH came with every tank fill and replace it. I squeeze it to see how much moisture comes out. Not very scientific but how much comes out does seem to vary - probably mostly with ambient humidity levels. I don't check the color changing beads every run but did at first. I know they take multiple tank refills to change color and require replacing. Especially if you have another reason to go into the gun it is also a good idea to look to see if there are any signs of moisture. (I have giving me more confidence my steps are working)
If you take reasonable steps to address the moisture that will be created by raising the air pressure and then monitor to be sure it is working there is no reason to fear moisture. I personally would not favor getting a tank and having it commercially filled. As long as the outfit filling your tank has good equipment and keeps it maintained you will be good but it will be more difficult to monitor to be sure they are doing that. I don't trust anybody including myself. But if you pick a good place to have your tank filled it could work great.
