Hello all. I have a betta in my 20 gal tank, along with 9 neon tetras. They get along great. I have recently attached a sponge to the front of my filter in order to keep the surface of the water very still for the betta....how ever, this causes i film to appear on the surface. I wanted to add some agitation to the water to eliminate this. Also, i feel as if the neons would do better overall with some water movement so i though i would add an airstone in the tank. Im showing 2 pictures because i wanted advice on if you all thought this was still calm enough for the betta to be happy. let me know.