So you have an air pump driven filter, which means bubbles are normal. However, there should only be bubbles in the back, behind the filter cartridge, and a little "waterfall" coming over the front spillway. Be sure to have the pump as close to the aquarium as possible, and trim off any excess tubing so you only have a slight slack in the line of 2-4 inches, max. The filter should be positioned so that the top of it is below the top edge of the tank by about an inch, and the water level in the tank should come to the spillway so water coming out of the filter runs right into the surface of the water in the tank. Please call 1-800-526-0650 after you make any necessary adjustments, if you still need help.
Date published: 2018-07-12