[BJ]

The scrubber monitor gives a graphic view of which part of the scrubber stack is being used. So, at the beginning on the dive it is the bottom. It moves up as you use more scrubber (the working part of the scrubber) moves higher in the stack. As you go deeper the scrubber works harder and the part in action gets higher up the stack. As you come shallower you notice some recovery of part of the scrubber lower down the stack. After three hours of diving with an Evolution with depths up to 50m my scrubber never got past halfway up the stack. Of course I would never really want the top part of the scrubber in action because that must be getting too close to CO2 breakthrough for my liking.
One thing the scrubber monitor does is give you a clear impression how the scrubber works and why you should NEVER repack a partially used scrubber. The computer download also shows the handset at any given moment in the dive and you can see how the scrubber coped. It's a good way to get an understanding.
A photograph of the actual computer display with a downloaded dive will be in the March edition of DIVER magazine.

On the subject of cylinder sizes, Big Mike has been diving a sectret military rebreather built by APD for the last year to depths up to 100m. It has only one litre cylinders. Alas, they have had to destroy it now - or they'd have to kill me!

He says that taking big bail-out cylinders with you is like buying a Porsche and tying a horse to the back in case you break down!