The debate has been going on for longer than I have been a member here over the use of silica sand vs. aragonite sand. One way to look at it is this, if silica sand leached silicates into the water, than a glass tank would be taboo since they are just melted silica sand! I have set up reefs with both types of sand and frankly, the only difference I could find is that since the aragonite sand is calcium based, it had a slightly higher CA reading. Since most of us dose or use CA reactors, that isn't really an issue to me. I am setting up a 75 reef currently and I am using silica sand, I just make sure it is rinsed very well.