That's about how I've always done things.
Remember though, eco-complete doesn't have any bioavailable nutrients. Sure, all the elements they list are there, but they aren't in the correct form. It's kind of like handing some one a chunk of wood and calling it a staple food for people, because it contains large ammounts of carbon.
Nutrients aside, eco-complete makes for a good substrate because of its varied granule sizes and relatively low density compared to gravel. Just be sure to pay attention to ferts at the start, and maybe give the substrate a boost through some other method.
And check for shells... my last bag had small shells in it that looked a bit marine.