it does look great mate.
my tap water pH is 4, with gh and kh barely detected, i just buffer my water with bicarb and epsom salts, and my tank is stable at pH8.1
i add 1 tea spoon of bicarb, and 1/2 teaspoon epsom salt per 20litre of water when i do water changes, and thats it.
I first set up with ocean rock and coral sand, until i learnt about epsom salts and bicarb.
I got up 1 morning to find my fave fish, a full grown Ahli, stuch in an ocean rock hole, dead, so i stripped the tank there and then, opting for play sand and slate.
I have never had a ph crash, whilst using the buffering methods described.
Whats your stocklist mate, I could see some beauties in your pictures