What are the pros and cons of sand and gravel? Personally, I have tried both and I don't see the appeal of gravel in tanka over three gallons. All my little tanks have gravel but my sorority has sand. It used to have gravel but it got so filthy that I got sand. In my opinion, sand is cleaner and so easy to clean. I just use my syphon to suck up the stuff on the bottom and once a month wipe the sides of the tank for algae. So, why do you use gravel? (if you use sand, why?) how many of you have tried sand?