So when I started shooting PCP's, I really appreciated the opportunity to work out daily by pushing that Hill pump down a number of times. I found I was having way too much fun with that so I found a used 45 minute SCBA tank with some life left, and got a fill station from Amazon for it. Works very well. What I'm thinking now is that I would like to get a small, perhaps 68ci CF tank that I would take in the field with me. The typical Ninja paintball ones I can find cheap all have the 800 psi output. What I'm wondering is if I can unscrew that regulator from the tank and replace it with one that is all set up as a filling station with a slow-release valve. I see them on eBay for ~$50. They have a M18x1.5-6H thread, that I think matches those Ninja tanks. Ninja's solution is over $200, not including tank. I can find a cheap used tank past it's prime and almost fill it from a full big tank. What do you guys think?