I used (4) 20-lb. bags of the Live Mesoflakes (aragonite crumbs, 2.7mm) and (3) 20.-lb. bags of Live Miniflakes (finer flakes) when I recently set up my 90 and absolutely regret not using it in the past! I love the way it adds the brightness and yet is heavy enough to not have a sandstorm when the current becomes a bit much. Love the stuff!