if you are sure that they are filling bottles by connecting them to a larger tank like the one you've listed then yes you would need the one you have linked.Im sorry but im very new to all this and really dont know the difference.
The scuba shop had a large tank like this one http://www.shutterstock.com/pic-23480836/stock-photo-scuba-tank-isolated-on-white-background.html
Would i need the one ive linked? http://www.fatbobspaintball.co.uk/Ai...duct_info.html