What works well is to get some cheaper argonite based sand from the bags from your LFS
, roughly 50 to 75 lbs. Then get 10-15 lbs of live sand from the LFS
that are typically sold out of their tanks to put on TOP of the bagged live sand. The goal should be to have about an inch or more of sand on the bottom of the tank. That will take 50 to 100 lbs of tank depending on your tank size. I have a 210 gallon tank with about 300lbs of live sand to give you an idea of the proportions. But when in doubt, more is better!