But the icreased bottom times everyone talks about are according to the dive planner charts. They mean you "could" dive longer because of the lowered amount of nitrogen. But you`re still going to consume the air in the tank just as fast as you normally would. Assuming your breathing rate doesn`t change and you`re using the same size tank, your actual bottom time won`t change. You just won`t need as long of a surface interval before you get back in the water.