I don't know man about that one. Maybe someone else knows these tanks. I don't even know if a Scuba shop would even fill a non DOT tank up or not. Plus, there is no mention of the connection for filling them to ask the scuba shop if they have that adaptor needed on hand.I would much prefer a USA DOT tank like a Scotts with a common and known CGA 347 connection. But yes, you would be able to fill a smaller tank with it with a double female foster hose. You would just crack the main valve open and let it fill slowly.I picked mine up on eBay used, but with a current hydro and a few years left on it as well, but I use my own compressor to recharge the tank now after expiration date. it is an 88CF and I take it with me wherever I go just like is shown.
Do your homework locally before you buy a tank to make sure you'll have a place willing and able to fill that bigger tank.-If you have volunteer fire companies around, check those since nowadays many have raised the money to get their own fill stations for SCBA tanks. Paid Fire companies generally (not always) do too.-Dive shops, although I'll add verify they'll actually totally fill your tank. Took mine to one only to find out after an hour and a half drive, they never mentioned they only fill to 1500 for walk in customers.-Paintball shops but again verify they'll totally fill that big bottle.-Google Fire apparatus/equipment repair centers. Most do more than just service and repair fire trucks. The good ones do hydro testing and refill of tanks for fire companies too and the one I found happily does walk-ins since they also serve the local paint ball community.
Double ditto and amen to the DOT certified tanks. It needs to be within it's 15 year life span, and it needs to have a current hydro test. Without those, getting it filled anywhere is a no go. This leaves out all of the CE certified tanks from Aliexpress, and many of the used tanks from Ebay.