I may just be weird but if it’s in the garage why not just place all the containers on the floor? If you keep them vertically it seems like the four would fit in less space than the shelves. Then you don’t have to worry about the shelves giving way or the containers ever falling and leaking. Maybe you could add a small pump to keep the water circulating if you want to keep it for long, I feel like still water is a bad idea for long term.
