I have a 130 in my tank. I have a 120 that is a 4X2X2 it seems to be doing pretty well. I have it in pulse mode and it has not moved the sand around to much. The flow directly below the pump seems a bit low but in the rest of the tank seems to have great flow. I do believe i need to move some rock around to try and get some different flow. I am super happy with it overall. I am sure you will figure out what works best with your tank.