My re-entry into salt water is a 20L. I put an overflow in one corner (see gallery). It is large enough to hold a power head for return, CPR Bakpak (left over from the old days), some live rock, and macro algae. It is kind of like a mini sump without the possibility of leaking. I have 2 65w cf now and plan to add a 70w hqi or two soon. A heater and a powerhead or two and your set. It is small, but affordable. It has been set up for 5 months now and is going well.