Originally Posted by SaylorKennedy
You don't need a gravel vac in that small of a tank. You should be doing 2 100% changes a week with maybe a 50% in between those. When you wash out the tank you'll be getting everything out of the substrate so there's no need for one.
Are you kidding me? 2 100% water changes A WEEK? You want me to kill my Betta don't you?
"A betta tank should never need 100% water changes unless working with medications. Too drastic of a change in water params can cause illness and death to any fish. Bettas can withstand more than the average tropical fish, and 50% changes are good for them if done frequently enough. The smaller the tank size the more frequent the water changes should be done. Anything under 2.5 gallons should have a 50% change every other day. 2.5 and more should have 50% changes at least twice/wk. If a filter is running in the tank, 50% changes once/wk are usually plenty."
Taken from the sticky in the Betta fish care section.