Have youe seen what happens if you click the "click here if you choose to disregard this statement" box? It's great. The pre-recovery dive candidate form. Comedy at its best, with a hint of a serious undertone.
Top site -a little too reliant on the gospel according to GI3, but it does lay it out in plain English & hopefully will go some way to dispelling the 'f*cking hell, too complicated for me, Trimix is for tekkies' argument. Past 40m it's a life saver. Helium is my friend, my best buddy, my soul mate. I want to marry it.