If you want ADA Amazonia, get the first version, not the second. Even ADA has admitted that the second version has had problems. I would use Flourite before I would use Eco Complete. People have had problems with EC affecting the KH of the water, and it is not a nutrient rich substrate, no matter what the advertising says. ADA Amazonia is nutrient rich, but so is mineralized topsoil costing next to nothing. The disadvantage of MTS is that you need to cap it with a couple of inches of some other substrate. The tank I am setting up now will have MTS with Flourite as a capping substrate.