Roger what are you using to heat multi tank system?
Looks good. Will you be placing any power heads in the back? The reason I ask is that all those surfaces are going to cause major drag and interfere with water movement in the tank. You will want to add lots of extra pump power to move water internally against all that extra resistance.
Dave.M
You might need some sort of lip or you will have snails on that freshly painted wall..lol