It is nice sand with a good CEC, so, yes it isn't "just sand". It is also not a usable source of nutrients, micro or otherwise. I like Flourite very much, but I also know better than to believe what the manufacturer says about it. Usable nutrients are in the form of ions - they are dissolved in water. Flourite doesn't dissolve. It has a good CEC, so nutrients from other sources can be adsorbed by it so they are easily available to the plants.