If it has threads on the top, you refill it like any other tank by taking it to a sporting goods store or paintball field. If it does not, then it is a disposable, and you cannot refill it.
Dicks, any paintball shop, and Gander Mt.
Yes, every few games, you will have to refill the tank, depending on the size. Without it, there is nothing to propel the paintball.
Call them and ask!
Take it to a shop! if you want to do it yourself the normal way is to put the bottle on scales and fill it from a larger bottle to a fill weight. To be honest though CO2 is well out of date. A smart move would be to move onto compressed air.
No, paintball co2 is much higher pressure.
No paintball gun will work without a CO2 tank or other propellant tank. without Co2 there is nothing to push the ball out of the barrel.
Where the air tank or co2 tank normally attaches
No, the FPS will stay the same. The size of the tank determines how many shots you can take before you have to refill it.
There is no such thing as a "CA" tank.
CO2, stored in the tank is highly pressurized. The paintball being shot is caused by it being pushed out by the rapidly expanding gas. CO2 also cycles and reloads the next paintball.
sure, gennerally there are 30lb co2 tanks and 50lb tanks that you can fill from, you will also need a fill station and instruction from a air smith on how to use it, so it is fairly expensive to own, but what a lot of people do it buy a fill station and then rent a co2 tank for the day from a welding shop or another place that will do it (scuba shops sometimes, propane stations, you just have to do a little searching) for a 50lb tank i think it was around $30-$40 so have everyone pitch in a few bucks and you are covered for the day