:listen: With lots of power outages, even during fair weather, I decided to go buy a battery operated air pump for my tank. The Penn-Plax model comes with tubing and an airstone seen here. It is mighty powerful with tons of bubbles coming out. The problem is that it is not "silent" as the name implies. It is annoyingly loud. It could be heard in the next room with the door closed. I think it even scared my fish, he was acting funny darting around the tank until I turned it off. I couldn't listen to music or watch TV with it on because it was so incredibly noisy. However, I guess I'll just have to suck it up if and when the power goes out. It's a good backup tool to have for emergencies and works great if you have a pair of ear plugs.