Rendering Error in layout Widget/Module: array_unshift(): Argument #1 ($array) must be of type array, null given. Please enable debug mode for more information.
Very nice,
I like the drawer sliding Idea. very smart.
The only negative I see is the span of the unit!
My advice would be to install a middle support tp prevent the wood from bowing. Which your top shelve has all ready started doing.
Rule of thumb depending what kind of wood you use but 700mm is the max span you should go with out support.
Any further needs supports.
The only thing with just that support it will only support the part it is attached to, the rest will still bow.
A way to fix it with out to much cutting is to get wood like 25 X 50 lengths of wood and put it under the piece of wood supporting the the draw runners, with the 50mm side facing you.
Just need two species and it should be strong enough to support the tanks.
Are you going to paint the cupboard or live it raw?