Best way to get ammonia and nitrites to zero is to let nature run it's course. May go fast, may take awhile, but the beneficial bacteria is THE MOST important part of a saltwater fishtank IMHO and i'm sure others will agree. So why try and rush things? =] Sit back and let nature do what it does best. I would hold off on adding any fish. It doesn't make the tank cycle better, only prolongs it, and is cruel to the fish. Putting a fish into a cycling tank is like taking someone from Maine in the fresh air mountains and making them live beside a dirty smoke stack of smog in LA for a month.
EDIT: That salt brand is used by many people on here and should be fine. From personal experience, during cycling the pH and kH can go out of whack here and there but will stabilize along with the other levels when it's finished it's first complete cycle. I say first complete cycle because even though people say "tank fully cycled" or "when my tank finishes cycling" but you're tank is always cycling. If it were fully cycled, well that's impossible, and it will be finished cycling when there is no more water in it anymore, lol.