You have decided that scuba diving is fantastic! You want to be a better diver–better buoyancy, better air consumption, better with drift diving, etc., and become a better diver overall. Maybe you have gotten so good with your air consumption that Nitrox will help you stay out of your decompression limits.
Additional training from great instructors can help immensely. We advertise the trainings with e-learning because this is the least expensive option.