set it up sump style with a sectioned off area for a refugium. You could always use this space to put an injured fish, pregnant fish, or just stuff it full of some water weed (anachris, hygro, etc) to help out a little with your water.
You won't have to buy any more stuff, and it will give you some space for emergencies.
You won't have to buy any more stuff, and it will give you some space for emergencies.
......