Corals aren’t the only form of life in our tanks though. A lot of the recommended numbers aren’t necessarily the most optimum solutions for anything specific, but rather an environment that everything can be healthy in.
Ex: it’s recommended that nems need Nitrates of 5 or less.
another ex: my Goni comes from Indonesia, and would be happy in 82 degree water. Do I keep my tank at 82? Absolutely not lol, because I also have fish and inverts that most definitely would not agree with that decision!
ex
#3: high alk, coupled with high Ca can grow SPS faster. But that’s a difficult path to walk, and easier to have a crash.
conclusion: recommendations aren’t natural laws, but are usually a good idea for most people in most situations.