I agree with Frenchy, it can and is being done.
I have a 3 gal. with no filtration, just LR and LS.
I perform approx. 4 cups of water change every 3 to 5 days.
I have read about others, who after 6 to 9 months of estabishment, have to do no water changes at all, just top-off with RO/DI.