Well single tanks are fine - great in fact if they suit the diving that you are doing.
I'd positively encourage you to get training before entering a cave or a wreck so we are on the same page there.
Only dive air? Well there are reasons why we don't believe that EANX 21 is the 'best mix' for diving.
Have a look at
GUE.com,
DIR Diver - Home, and
DIR Diving Better still say hi to me at Vobster sometime and have a chat.[/quote]
thanks Clare - i get to vobster a fair bit, its my training puddle for my new (and first) drysuit... if i ever spot ya ill come say hello