I am doing research on calcium reactors and was curious if everyone on here that uses one does an exchange on their Co2 tanks or if they own their own and have them filled when empty. If you own your own tank where in the area do they fill personal tanks at? I am trying to figure out if it would make more sense for me to purchase my own tank or to do an exchange. So far I have purchased everything i need to get a calcium reactor up and going with the exception of a Co2 tank. Thank you in advance.