Simon, I do not use HP tanks I am content with a plain old aluminum 80 that is what most people including my regular buddy use so I like to be able to match my dive partners volume if I stay shallow like anything less than 20' I can usually manage a 1.5-2.25 hour bottom time. Allen, OK got it Brookhurst and Edinger, I have not been in the water for 1 year myself since I seriously injured my hand but the only problem I can think I might have is with my buoyancy I might need to tweak my weights a bit. I also have room in my Jeep for 3 people and gear. I only plan on doing a 1 tank dive.