38 Gallon Mixed Reef Cube Newbie

[Frogger]

It could be a combination of things, higher nitrate and Kalkwasser. Zero phosphate is not good. I lost half of my corals a few months ago when I let my phosphate get to 0. I was dosing KNO3 at the time and as the KNO3 increased the corals, the algae, the coralline algae all starting using up the phosphate and it crashed. I was running GFO at the time which made it worse.

I need to add nitrate to colour up my corals. So I am now adding KPO4 to keep my phosphate at a readable level and adding KNO3 to keep my corals colourful.