water changes in a 1.5 gallon tank

I got a new 1.5 gallon tank for my Betta about a month and a half ago.It has a carbon filter that is attached to the side of the tank with suction cups and gravel.I was just wondering how often I should change the water because I have been reading different things everywhere I check.I have been changing about 1 quarter of the water once a week and doing a full water change once a month. What I am doing seems to be working the water is crystal clear and not really smelly , more importantly, the fish seems to be happy in the new tank.I was just wondering If I needed to change the water more often or just stick with what I have been doing.

 

I do 50% water changes weekly, sometimes more if there's a problem. But if your fish is OK, then I think that sounds OK. Especially that you have a filter (I do too).

 

are u aware of the aquarium nitrogen cycle?

 

The good thing about such a small tank is that you can do water changes with a measuring cup.

 

yeah that's what I do