I agree with pulpfiction. When it comes to dosing you reef, you have to be very careful. I defiantly recommend finding out what the repercussions are (good and bad) before adding anything to your tank.
Keeping up on your water changes is the best advice I can give you regarding tank chemistry. Your tank will receive the majority of its supplements from the fresh saltwater. Once you have a better understanding of the chemistry in your tank, you may want to begin dosing as required.
As you begin to add more corals, inverts etc., you might find that some of the supplement that you need to keep you livestock happy is being depleted way too quickly. For example. If you decide to have a lot of SPS/LPS coral in your tank, some sort of calcium additive will be required. Or if you have a lot of mushrooms/zoas in your tank, iodine will need to be added to the system.