I'm a vacation diver at the moment. Got certified about 19 years ago with my open water course with padi. Then I just picked up diving again over the past year and a half where I have done some fun dives and I just recently completed the SSI Advanced Adventurer (including the following dives: drift, wreck, navigation, night and deep [30m]) I also took the nitrox course. I only have like 13 dives total and am still working on things like buoyancy and air consumption. I am wondering where to go from here on future dives and training. I would like to do the deep specialty so I can get certified down to 40m. What other courses are worth taking?