Why can a diver go further in fresh water than salt for the same pressure?

This is not true, a diver can go deeper in salt water than in fresh water for the same pressure. Salt water is denser than fresh water, so it exerts a greater pressure on the diver's body. This means that the diver must wear more weight in order to sink in salt water, and they will be less buoyant than in fresh water. As a result, they will need to use more energy to swim in salt water, and they will be able to descend less deep for the same amount of effort.