All of those parameters are ideal in my tank the only issue I'm running into is the KH. It seems the only way to keep my PH up to that value is to add supplements that maintains the PH. When doing so my KH rises. I know that the PH is of more important so I just wanted to clarify that the KH really only effects corals and such.
I do water changes regularly and test on a regular basis and everything from nitrates to ammonia are 0.
You sound like you're experienced with salt water tanks, which is an advantage.
Using aragonite sand (or adding some) will help keep the pH steady in the aquarium. You can use a buffer, as you're already doing. Some salt mixes aim for a slightly lower pH than others, because some tank owners think it will help the fish.