Originally Posted by slug61
Well, in my case, 1 gallon is almost half the tank. I have a 2.5gallon.
Then I'd do like 1/2 gallon changes. You really don't want your nitrates over 40. Long exposures to high nitrates is like secondhand cigarette smoke to humans and it does damage over time, especially if you're exposed to a lot of it.
In that tank size, even cycled, you'll probably need 2 weekly changes because nitrates still build up faster. The only way you could do one change or possibly less weekly is if you have live plants.