Safety rules- dive computers. The most important safety rules using dive computers by Hardy.
Plan dive and dive as You planned.
If two independent computers condemn various parameters decompression- select this longer.
In the follow multiple dives as first You should do deeper diving.
In the multilevel dives always do first dive to the deepest depth.
Avoid dives deeper than 30 meters, avoid decompression.
Do not make a dangerous dive profiles- "yo-yo", "saw-tooth" type.
Break in the surface should be no shorter than an hour.
Do not exceed the recommended rate of ascent, always follow the safety stop.
Always prepare a contingency plan, keep a safety margin.
That's it. And so much.