> What type of regulator do people use for Argon, and why? A MK2 scubapro. Because that's what I had spare. Main problem is lack of IP adjustment - someone suggested cutting the spring but I havn't tried that (yet). > Also do you > use a pressure relief on the 1st stage (for freeflowing reg.)? Yes. No idea where to get them in the UK. I got mine from Mar-Vel in New York for about $35. David dajm@xxxxxxxxxxxxxxxxxx