Waterdog makes a good point.
Besides, a cycled tank will consistently provide lower ammonia and nitrite than a tank that's changed twice weekly. What you want is 0.0ppm ammonia and nitrite all the time; and that's only possible in a cycled tank.
That's why I always recommend cycling the tank, even the smaller sizes. Use additional foam in the intake and/or outflow to provide more area for your nitrifying bacteria colony. A good sponge filter can provide that area and low current flow for the fish's comfort.
A weekly 50% water change and gravel vacuuming is still necessary to remove DOCs (dissolved organic compounds)
The Whisper 3i is NOT a good sponge filter. It's a bad design which does not provide water flow over most of the filter media. The pump is fine for a small tank. Get an inexpensive sponge filter and cycle your tank.
Last edited by Hallyx; 02-13-2013 at 06:41 PM.