[Mal Bridgeman]

Originally Posted by Digger

I've been thinking about getting a water vole for the rebreather, it could just walk around the loop and if it dies I know I need to bail out.

Digs.

Vole ? What kind of madness is that? Where is the precedence? You'd have to be some sort of halfwit to dive with an unknown piece of kit like the vole.

No, what you want is a canary. Their skill in reliably determining the unsuitability of a breathing gas is legendary. Since the mines got closed down, there are an awful lot of them unemployed nowadays so you should be able to pick a few up cheaply on the street corner. (Do buy a copy of their Big Issue first though).

I'd recommend diving with two initially till you get the hang of them, then introduce a third if you are unsure. The third canary should be fitted with the VR3 connector though so you get instant feedback on your imminent demise.

HTH
Mal