Well the plants won't be grown from the crates. The crates are just there to create a layer of very slow flowing water beneath the sandbottom.
Reversed Osmosis water is fed into that water layer and then slowly moves through the sand bottom upwards.
When necessary for the plants I can also dose some fertilizer in the water beneath the sandbottom.
So it's a bit between a Jaubert plenum used in some reeftanks and a reversed undergravelfilter.
I really can't get over how awesome your tank is going to be, I really like how you made the 3D background and would really like to do something similar
Can you give any tips or advise ? I must of missed it but can I ask what kind of epoxy did you use? does it come in different colors or can you add pigments to make it the shade that you want ?