Filtration may minimize the need for water changes, but it doesn't end it altogether. The only way to end water changes is to create some sort of nitrate-to-oxygen device and attach it to your tank.
The Red Sea Art Deco nano filter is a good filter for a tank of that size. It has an adjustable flow rate and creates very little current. PetCo usually carries them.
There's actually a bit of a trick where you get a small plastic bottle (coke, sprite, whatever) and cut the middle part out of it so that you have a circle. Cut it somewhere and stick one part to the filter and let it curl around the output. That what I did and it really helps against the current.