I have used silicate quartz based sands in all my tanks without a single problem. I don't use a phosphate reactor and have no silicate issues or phosphate problems. It is all hype to get people to spend more money. While there is no downside to using silicate based sand, there are benefits from using aragonite based sands. The aragonite acts as a natural buffer against changes in pH. Albeit the system would have to have pretty drastic pH dips, it does seem to maintain proper alkalinity and pH balance. Also, silicate sands do not breakdown unless under extremely acidic conditions for a marine tank.