If a diver needs to go to 75 feet for 30 minutes, but the dive computer's plan mode shows 70 feet for 30 minutes, what should the diver do?

The most appropriate action for the diver in this scenario is to extend the surface interval until the dive computer's plan mode indicates that it is safe to dive to the desired depth of 75 feet for 30 minutes. This approach prioritizes safety and adherence to dive computer protocols, which are based on established decompression schedules and no-decompression limits.

Diving beyond what the dive computer recommends can significantly increase the risk of decompression sickness, as the computer takes various factors into account, including depth, time, and the diver's previous dive profile. By extending the surface interval, the diver allows for proper calculations to reset and accommodates any nitrogen loading that may have occurred from previous dives, ensuring a more secure and safe dive profile for their upcoming dive.

While the option to begin diving at 75 feet might seem reasonable since it is close to the planned depth, it may expose the diver to unnecessary risks. Similarly, reducing the safety stop time or choosing not to dive at all does not address the critical need to align dive times and depths with what the dive computer safely recommends. By waiting until the plan mode suggests an appropriate dive profile, the diver maintains a strong focus on safety practices that are fundamental to scientific diving and personal well-being underwater.