The best way to treat your tank's chemistry is to learn how to balance magnesium, buffer, and calcium. Here's how:
1. use a good salt mix. They vary in how much magnesium and calcium they contain. I like Oceanic, because I run stony coral (coralline is, if you like, a stony algae, and goes right along with it. I have to scrape it off my glass---a lot.)
2. do weekly 10% water changes. This replaces trace elements like strontium, iodine and such that get used up in such tiny amounts, but that need to be there. Crabs and shrimp need iodine, particularly...but dosing iodine: that's for way beyond a beginner tank. Right now, regular water changes can supply all you need. And NEVER dose any elemental chemical into your tank that you don't have AND USE a test for...
3. Everyone should have an alkalinity test and a ph test. I use Salifert DKH ALK test and a ph meter. Test, if things look 'off'.
4. If you are going to have stony coral, clams, or want a lot of coralline, eventually you'll need the Calcium test and the Magnesium test...and magnesium additive. I use Kent Tech M.
5. Always follow bottle directions. This is serious. Do.
6. Keep a log book. These numbers will get confusing if you don't write them down as you test, with date.
7. Your best water readings are: magnesium 1280. Calcium 420. Alkalinity 8.3-9.3. Salinity 1.025 (range is 1.024-6), temperature from 78-82: try not to exit that zone; and other chemicals best handled by water changes: there will be a lot of elements you have only heard of in the periodic table, and will never dose. But cheap salt is not always a bargain.
Keep your mg (magnesium's chemical symbol) at 1300-1400 with those readings and you'll soon be scraping coralline too.
HTH.