Originally Posted by sholee
Have you tested your ammonia levels in your tank?
There's your bottom line, right there.
Water change schedules will vary depending on your natural pH, your fish's (and other stock) ammonia output. How careful you are to remove feces and waste food. What kind of substrate you have. And other variables.
Water testing, especially for ammonia, is a more personalized method of establishing a water change schedule. You want to keep the ammonia well under 0.25ppm. Ideally, you want it at 0.0ppm, but this is only doable by almost daily water changes or a cycled tank.
Cycling is not for the keeper's convenience; it doesn't cut down on water changes that much. Cycling is for the good of the fish.
Having said that, any size tank can be run without cycling if you change the water frequently enough. And, as always, bigger is better.