Review on NEXBERG Aquarium Air Pump: Mini Piezo Air Pump for Fish Tanks up to 13 gal - Super Quiet <35dB, Ultra Silent Nano Energy Saving 1W with Free Thermometer, Check Valve and More! by Jimmy Jefferson

The rock produces enough bubbles to be used in a Betta aquarium and it breaks down the biofilm on the water surface in my tank. I keep mine in the corner so it cleans about 3/4 of the surface. I suspect if placed in the center it would destroy the entire biofilm. The pump works as it should. The only thing I complain about is that the part of the suction cups that wraps around the sewer pipe doesn't hold them very firmly. The cups should be aligned in a perfect straight line so the handles will hold the pipe. If they don't line up in a straight line up and outside of the tank, they won't hold onto it. Better quality suction cups can easily be purchased at the pet store for air hoses. But as long as the ones in this set are straight, they work.