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.
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
There is no such thing as a "CA" tank.
A paintball gun, unlike airsoft or real firearms will have a hopper on top, and will have a co2 tank sticking out of the back.
you need Co2 to fire any paintball gun, it is what physically moves the ball out of the barrel.
No, any tank will work.
Depends on the connections.
unscrew the tank, this will vent any co2 that is in the marker out the asa
You cannot unless you have a gauge installed, or know the exact weight of the 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.