Very nice aquascape. A sixline would love all those holes.
Depending on whether or not you want corals, I would think about adding another powerhead on the left side of the tank aimed towards the one on the right.
There's no need messing with the pH or alk
of a newly established tank. Most new tanks have a low pH but once the water params stabilize over the next several months the pH should be around 8.1-8.2 by itself and stable.
Wow 540ppm for the Ca
. At least you won't have to dose!