I’ve never done a real night dive. Only in my open water course but that doesn’t count.

I learned that we never turn off the light in the water. What about the backup light. Do you turn this on before diving as well?

Admittedly I've only done the one real night dive so far, but we turned off our lights to observe the fluorescents. What reason were you given for not turning them off? was it just a safety thing from there point of view to be able to track you?

We were told never to turn off the light under water in case the light doest turn back on again.

What we did is hide the light under are BCD to see what no light looks like. I thought this was a PADI directive to never turn off the light under water.

Can't see anything about never turning you light off in the PADI adventures in diving manual.

Perhaps the dive school had other reasons like the equipment or experience..

It must have been the teacher’s preference then.

My original question is therefore answered.

I never turn my light off when doing night dives, simply because I think the switch is probably the weakest link if it is going to get flooded.

Also, it can be fiddley to get back on / if you drop it when it's off, it's going to be a pain to find.

When I wanted darkness, I simply press the torch against my leg/stomach.