As far as context goes, you are absolutely right. You can learn about reef chemistry on a forum about as well as you can about flying a plane. You need to get your hands wet before you get a real grasp of what's going on in the tank.
To oversimplify it... saltwater is made up of all kinds of stuff. Corals use all of those stuffs as building blocks for their reef building skeletons. What is a reef made of? Sugar of course. Through photosynthesis, the energy of the sun and Co2 in the water is used by the symbiotic algae that lives within the coral tissue to produce carbohydrates (sugar) that bind with calcium in the water to form... you guessed it, calcium carbonate. Instant reef.
Now I know what you're thinking, "I thought you were going to over-simplify it Shawn". Well, here's the easy part; you keep track of the stuff that gets smaller like calcium, and add as much as it takes to get back to the magic number. We are fortunate enough to know what natural sea water (NSW) is comprised of so we know the target numbers to shoot for... and no, you cannot improve on mother natures evolution so stick with NSW numbers.
Here's where you could potentially screw up...
1) You use the instructions on the label to dose for x number of gallons. You are dosing for your bioload and consumption, not for bulk system water.
2) You don't have fail-safes in place and accidentally overdose.
3) Your test kit lies to you and you think you are too low with one parameter when in fact you are too high and getting worse.
4) Missing the balance between lighting, water quality, Co2, salts, and elements.
5) You start a roller coaster effect by adding too much of one element then overcompensate with another.
6) Bad chemicals that have either taken on moisture, or fallen out of solution with age, or have become more concentrated due to evaporation.
7) Listening to bad advice or misinterpreting good advice.
8) Following the misconception that you need to put pressure on your corals to grow by continually adding more chemicals.
9) Not allowing corals to adapt to the elevated heavy metal levels of our captive reefs.
10) Misc. human error and calamity.
The good news is you are starting off with a huge volume of water and very little demand for replenishment. Your learning curve will follow your stocking curve. The bad news is this whole reefing thing is like buying a lottery ticket. Having good advice and arming yourself with the right equipment is like having a thousand lottery tickets, but it's still a lottery when nature is at play