Is the pipe where the water enters the 55 gallon tank submerged or is it above the waterline? If it is not submerged try submerging it and see if it still creates bubbles. If it is submerged and is still causing bubbles in the tank then the drain pipe the water is coming from is sucking in air. You can fix this by using a durso standpipe if possible. If you can't do that then you could make a bubble trap out of a piece of larger pipe. Put the larger pipe in the 55 gallon with quite a few small holes in the pipe under the surface of the water. Put the drain into the large pipe so the water has to go out the holes in the pipe under the water. The pipe should stop all the bubbles from going in the rest of the tank.
B