All salts on the market today seem to be much the same, there are good batches and bad ones. I use instant ocean at the moment, and have no complaints. Sand is a personal choice, I prefer a bare bottom tank but others have a deep sand bed. Most sand for the marine tank is made up of aragonite, which helps buffer the pH. Live sand is another popular choice, but I don't understand how the beneficial bacteria stay alive for months in a sealed bag..........