I just made a diy co2 "device" and it is causing a lot of "soapy" bubbles on the surface of my 10g tank. Does anybody know if this is OK? There is no leaking from the bottle into the tank that I can see. The device consists of a 2-liter soda bottle and a tube with a check valve and airstone at the end. I've heard that some people add a second bottle to catch any liquid that might get into the tank, maybe I'll add one, but like I said, I don't see any liquid leaking into the tank. Thanks!