What's your bioload? I've had a 12 gallon nano with one clown, plenty of coral, one cleaner shrimp, and a very large anemone in mine for almost 4 years. I've done maybe 3 water changes in all of that time. I make my own ice cubes with a very nice assortment of goodies for my tank and I feed one ice cube a day. I also feed my anemone about 1/2 a silverside 2 times a week. Everyone is fat and sassy, growing very nicely and all I do is add r/o water. I top the tank off every day so my salinity stays in check. I haven't had any kind of algae outbreak in over 2 years. I clean my glass maybe once a month. My growth is spectacular. Cut back your bioload and you can probably drastically cut back your water changes.