Usually about 1-2 pounds of LR per tank gallon capacity provides the best benefit from having LR.....besides, you can buy some LR and some dry base (which is cheeper) and the dry will become live again in about 6 weeks, and look about as good as live stuff in a year.,I used 200# of LR in my 475g build and bought another 130# of dry for it when I set it up, and have since added another 100 of dry, and will add another 100# to it later this summer. Just make sure any dry base you would get is actually ment for saltwater systems, not fresh water tanks.