How long would it take for the rock to have die off? I could place the corals and rock into my main tank right now. Fish wouldn’t work as it’s only a 30 gallon 3ft.You need enough to cover the rock if possible. The fish and rock can stay in a tub for awhile while you mix and make more water.
It takes a long time to make water and get it up to temp. That’s why you want as much as you can ready to go.