Years ago I filled my cylinders at a scuba place, then that died out. So at the same time I bought a Bauer Oceanus pump powered with a 5.5 HP Honda engine.
Fills my SCBA tank in minutes. I was really lucky to but it used, new Oceanas are north of 5000 bucks I hear. Probably more now that the dollar is overprinted.
Anyway I have unlimited easy air now.