Optimal water chemistry is much more than a set of perfect numbers. It is an over all balance of many minerals, as well as an ability to maintain stability over long periods of time. When excellent water chemistry is achieved you can see it in the animals. The polyps may be a bit larger and extended, new active growth tips will form more quickly, or the corals will just have that extra glow or sparkle that the observant reef keeper will appreciate. Testing often and paying attention to details will train you to be able to see when parameters are beginning to skew. After many years, I began to see various cues when testing that helped me form opinions as to why the corals looked better or worse on a given day. I started to realize where the sweet spot was for levels and began to shoot for stability of these various parameters rather then chasing that perfect number. Through the years, opinions on where one should keep these numbers varied greatly as more knowledge was provided to the hobby. At one time it was believed that keeping elevated alkalinity or calcium was the best practice. More recently the trend to keeping these closer to natural sea water levels has been more popular. Finding that perfect number or sweet spot takes time and patience. Close observation will help you master this and then the ability to keep it very stable becomes most important. Rather then give you a specific set of parameter to follow here I would suggest to strive for stability and shoot for levels as close to natural sea water as possible.