I was going to wait until I relocated to start this project, however due to my impatience, and the fact that a move may be more than a few months away I am going to do a test run... (on a smaller tank for the moment).
I am going to use JBL AquaBasis plus for this project.
I have 12.5kg's of the substrate which is sufficient for a 250L tank
JBL AquaBasis plus
Nutrient Substrate for Aquarium Plants
Product description
* Contains all essential nutrients such as iron, minerals and trace elements.
* The clay particles act as a nutrient store, binding excess nutrients and releasing as required.
* Does not require mixing with gravel.
* Does not contain nitrates and phosphates which promote the growth of algae.
JBL Aquabasis plus plus contains the full range of vital nutrients as well as iron and trace elements which aquarium plants need for healthy and strong growth. These nutrients are provided in depot form and are fully accessible and available to the root of the plants. JBL AquaBasis plus promotes rapid rooting and results in healthy and strong root development.
I will use a paint scraper or similar to angle the substrate so it is deeper towards the back, as I intend to use Quartz based sand as the top layer (which is a much lighter colour than the plant substrate)