Since the local water supply switches sources often which results in varying KH ranges, I use 100% RO in my tank. I do not reconsitute or buffer it. I only add ferts (NPK, Traces, Iron). I have no erratic pH swings, no Ca/Mg deficiencies, and not one speck of algae. My triple orange Apisto caucatoides is doing great. Heck, I'm growing some of the best plants I've ever grown!