My buddy and i are planning a shore dive. we’re descending onto a very gradual slope that begins at 5 metres/15 feet, so our descent and ascent will be a gradual part of swimming out and back underwater. we have similar cylinders filled to 200 bar/3000 psi. we plan: • 50 bar/500 psi reserve. • 20 bar/300 psi for our safety stop. • to turn the dive when we’ve used one-third of the air available to use on the dive. this means we should head back when either of our spgs read