Calcium Hydroxide/Potassium Bicarbonate, 50/50, as much as it takes, which will depend on fish load, rate of feeding, filtering. It's impossible to define other than applying and observing results in your system.
Thank George. Looks like we don't have a clear cut of rate to be applied. I understand what you meant. Thanks
I use potassium hydroxide and garden lime (separately) to raise pH. The lime provides calcium. It you have a smaller system you might want to use carbonates to better buffer the system but for larger systems the hydroxides are easier to make adjustments. As for doses it's trial and error. Start small.