@Wibble
It’s interesting the discussions either way on this. I had logical reasons to change from an octopus to an air2. Then had logical reasons to change from an air2 to an octopus.
The reasons to change from an octopus to an air2
1. The ABLJ had an optional extra of a direct feed that was fitted between the ABLJ mouthpiece and the hose. The connection between the mouthpiece and direct feed was not perfect and the mouthpiece would sometimes come off.
2. The octopus had a tendency to hiss and drag in the muck.
3. Had just acquired a decent 2nd hand regulator to replace the scabby spiro and it didn’t have a octopus.
4. Had just got myself a drysuit and the first stage only had 3 lp ports. At the time didn’t fancy additional adaptors on top of the 1/8 to 3/8 adaptor.
The use of an air2 resolved all of those issues. Was the air2 (mk2 version) more bulky? No as it was shorter but slightly fatter. Was always removed from the ABLJ and serviced with the regulator. It should also be noted that the training at this time for air sharing was buddy breathing and no training for octopus use. Also was taught to use the drysuit for buoyancy control.
So why change back to an octopus?
1. Invested in a jacket style BC. The connection between the direct feed and mouthpiece was much improved and didn’t fall apart. There was plastic D rings and Velcro to hold things to like an octopus.
2. Started to get involved with training. There was a tendency to press the air2 purge instead of the deflate during a controlled buoyant lift. Having oddball kit didn’t really work.
So bit the bullet got an octopus and T piece to fit it too. My present regulator has 4 Lp ports at 3/8 so no adaptors required.
would I change back to an air2? Unlikely.