I also run a smaller tank (14g) and the Tunze 3152 nano ATO is a great investment. I have a 5 gallon reservoir that it pulls from and I go through about a gallon a week. Nano reefing is a slightly different ballgame than a larger tank, because even slight environmental changes can affect such a small volume of water quickly and shock your inhabitants. In other words, we have a MUCH smaller margin of error and our levels can shift very quickly. When I was manually topping off water, I did it 3 times per day, so the impact on SG was minimal. Adding an ATO is a wise investment that will both stabilize your tank and reduce your manual maintenance.