What additives should I add to my reef tank and how much?

[Mykiss]

I've checked the above stickies and have noticed that there's a lot of focus on adding calcium and Magnesium (and also maintaining alkalinity and pH).

In the past I've kept a marine tank and it has done ok e.g. corals surviving. All I've done is do my weekly and sometimes monthly 15% water changes and add calk water now and then. I've never tested the water.

I'm planning on setting another marine tank (45 gallons) with a 175w metal halide and was planning on moving some of my livestock into the new tank. These include some purple, brown mushrooms, riccordia, hammers, pulsing exina, white bubble tip anenome, star polyps, some zoos, and that's about it. This time I want to do water tests and keep water parameters where coral growth will occur and have the tank thrive and look great.

Question #1
what additives should I be adding into the tank and at what readings should they be? e.g. calcium, magnesium, iodine, Strontium & Molybdenum

Question #2
what is the ideal water temperature for happy corals and what salinity?

Thanks

I hope this thread will help many beginners like me.