I have no idea how to help you, but I love the idea and can't wait to see what comes of it!
It seem like nobody else really does either. I guess I'm basically on my own
for the substrat:
cat litier 50 % ( no parfumed) or calcareous loam
river sand 12.5%
pouzzolane 12.5 %
vermiculite or perlite 12.5%
calcareous sand 12.5%
2 perlite
2 vermiculite
1 small sand (for aquarium), 1 fine white sand
1 pouzzolane (volcanic lava)
1 aqualit (expansed ceramic for aquarium). The aqualit can be replaced by 1 of pouzzolane.
P. moranensis would be another great choice for this wall. Excellent to see progress on this.
excellent this work.
OK for the substrate also
you can use aquarium pump , but see on its user manual , the maxi level to have a good working.
I have use this method from my mini wall with sucess.
your mini wall = 90cm x 30cm no , but you can use the 2 positions in height 90 or 30cm
jeff