Saltwater is not hard. If you are doing fish only then your lookin at a very similar maintanance regime as freshwater. In fact ud prolly be doing less because you can do a nice refugium to grow plants in and a monter sized protein skimmer (dont work in freshwater) and that will remove most of the waste produced by the fish. Most salt water fish couldn't give a hoot about some nitrate as long as its not excessive. Its only when u start getting into reefs that it becomes more difficult and u need to worry bout keeping nitrates, nitrites, ammonia, phosphate, silicate at practically undetectable levels and keeping your calcium, alkalinity and magnesium up. But even then, once u reach a balance its very easy to maintain. I started saltwater because I wanted to be challenged because freshwater was just too easy. When i started i found i was not really challenged at all...