Sand or Gravel?

generally, nutrient-less substrate is better suited for decorative purposes, and the main substrate in which plants will be planted will ideally be something like aqua soil. There are of course other planting substrates, and methods of turning other nutrient rich products (dirt, kitty litter, etc.) into substrates though it may take some preparation. I'm not that smart so I just use aqua soil.

 

No question, you can grow aquatic plants in plain quartz sand, if the particle size is not too small. You can rely upon water column fertilizing totally. That doesn't mean that quartz sand is better than, as good as, or worse than expensive substrates. It is just one option. Some plants will do much better in the more expensive substrates, but there are a lot of very nice plants that won't care much what substrate you use.