I just replaceed my tank to a 20 gallon long so thas about whats up with mine.
As for corals, I cant help you because Im a beggining as you are in the salt world, and especially corals, so sorry I can help, but Wayne, SReef, or Camaro will all know exactly what your looking for.
I keep my salinity around 1.024 or as Wayne said above 1.025. either is fine I just tend to keep mine at 1.024, no real difference though.
As for the fish king, yes I do look at myself as a fish ki.... naw jk. I am no where near a fish king, almost anyone can put me to shame on salt water knowledge lol, and freshwater for that matter hah.
As for your last question about dosing chemicals (im gussing you mean like trace elements like calcium and such, I again cant help you too much, but it will depend on what type of corals you have and their own requirments. But as I said above theirs alot better people to help you out with corals and such.