I don't really know
. I
assume that they fill them there, in fact it must be since he checked my tank first for expiration. But you might want to call and make sure first. Since I discovered that mine had expired I bought the filled 5# from them and that was $125
. Like I said, high, but when you're between a rock and a hard place. . . . They quoted me a price over the 'phone of $45 to fill a 10# so I suppose a 5# would be approximately half that. The guy did mention (I believe it may have been the owner) that about 20% of their CO2 sales were for aquariums
.