At what levels should the various parameters be maintained?
This is a tricky one. You can aim to replicate natural seawater levels or you can opt for levels that have evolved over the lifetime of the hobby. In reference books you’ll often find discrepancies regarding natural sea water parameters, although the sea can largely be considered stable there are variations. Variations in salinity, temperature, and calcium are widespread, changing with depth, season, atmospheric pressure, and proximity to land. Locally these can change over the course of the year. We are primarily concerned with seawater from tropical latitudes in the vicinity of coral reefs so the figures I’ve quoted reflect this. See: Reef Ramblings – Recommended Reef Tank Parameters.
