I don't blame you on the free shipping bit I'm sure they'll return it. I would mix a small sand/Eco batch first before to see if you like the look. IMO for depth I would have done the first layer with sand at a grade from high to low in the front and then cap that with the Eco while leaving a small gap between the sand and glass in front you can fill with Eco complete. Looking forward to seeing what you do with it.