The reason you won't be able to get your mini scuba tank refilled it because dive shops are going to require you to produce proof of diver certification before they will agree to refill a mini scuba tank, or any scuba tank, for that matter.
The link below has some good information about mini scuba tanks. You'll have to scroll down past the illegible blue text in order to find the readable stuff, but it's worth it.
where to buy mini scuba tank which is suspended from the mouth . it ...http://www.divingshops.netFri, 29 Apr 2011 00:54:33 GMTi saw it in baywatch – yellow in colour. very light in weight. A dive shop. There are two popular brands sold on the market. Spare Air and H2Odyssey. http://www.spareair.com/product/models.htm.