Co2 filling locations...

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.

 

Thank you for the input everyone...at least now I know i have a few options available to me as to where to look...some of the places I called were welding supply stores and they would only exchange tanks with their company marked tanks as they stated personally owned tanks sometimes do not get inspected or get damaged through wear and tear. I dont imagine much wear and tear occuring on a tank sitting inside a aquarium stand, but i can see their point as far as farming and welding use goes.

I live about 40 minutes from Cedar Falls Scheels and about a little over an hour from Scheels in Jordan Creek Mall in West Des Moines...so Scheels in either location as well as Leydens & Associates in Des Moines look like the big winners for me as far as places to go. Thanks again!