Any aquarium can be made reef ready with just a few cheap moves, regardless of whether or not the glass is tempered. If the glass is not tempered, then holes can be drilled in the bottom in order to install an overflow and a return. If the bottom is tempered, as you’d find on larger aquariums, then the holes can be drilled in the back wall or sides of the tank. These panes usually are not tempered, but if they are, you could resort to a continuous siphon overflow, though we do not recommend these setups as they are prone to getting clogged and causing all sorts of headaches. The point to all this is that if you’re on the hunt for a used aquarium, you don’t have to pass up a great deal on a non-reef ready aquarium. You can certainly make one of these tanks reef ready for next to nothing.