Water Parameters

[Saltysteve]

Just wondering, I finished the weeekend water change and testing etc. Is it normal for water parameters to never change? I do not add anything (anymore) accept RO water (top off) and water changes.
PH 8.3
Calcium 420
ALk 9.6 (3.43)
Temp 76
Nitrate 0

I am getting little growth accept hair algae and coraline!
I would post a picture of my results from 9months, if I knew how