There are quite a few choices to make when you buy an Octo.
Of course a major consideration is always the price.
As with the Regulators, you can also get Balanced or Unbalanced Octos.
Because they are only ever used as a backup, majority go for the unbalanced as it is cheap and simple.
The 4 main types of different Octos are described below:
The first is an Octo attached to your BC hose. This saves an extra hose from the first stage but has three disadvantages:
- It makes a big “block” on the left hand side and makes dumping the air awkward.
- It requires a non standard hose to provide the high volume of air. This means your reg won’t work with any other BC.
- In an emergency you need to give up the primary on a short hose and breathe off the BC octo, not ideal to say the least.
STANDARD UNBALANCED OCTO
This is a simple unbalanced octo on a long hose.
Does the job.
No nonsense and a good choice.
Will require more frequent adjustment if you have a balanced primary.
The advantage of these is that they are ……well small and compact. Very nice to dive with.
They also work up side down, but the quality is a bit cheapish, the covers tend to break over the long term. But there are plenty of spares.
BALANCED ADJUSTABLE RIGHT-HAND OCTO
This is the ultimate!
The right hand hose means it does not have to curve, it is immediately in the correct position.
This is a top of the line balanced Octo, so breathes exceptionally well and in addition lasts a lot longer before services.
Adjustable means that it can be “de-tuned” for normal use and then opened up for emergencies. Prevents the octo free flowing.
It is essential to use a balanced octo with an “overbalanced” first stage (one with an environmental sealing system) Unbalanced will free flow at depth.