CaribSea Agra Alive Reef Sand is very good, I used it on my 2.5g nano and it has worked just fine for me, but, in my 55 gal. tank I used beach sand, all the live rock I used is from the beach and the fishes, inverts and other LS came directly from the beach too, and my tank has been up for more than 3 years perfectly. The only problem is that you have to cure ALL of the LS(other than inverts) for a minimun of 2 weeks before adding it to your main tank. Good luck