I am going to be setting up my new 55 gallon in the next month or so. I have decided on what I will be stocking and next is the substrate. Has anyone used the Eco Complete Cichlid Sand? I can get it for 19.99/20lb. How much should I buy for a standard 55 gallon tank? Beyond sand I will just have natural rocks for decoration. Any thoughts on this substrate? Good choice for mbuna?