I am getting ready to change my return pump design in my tank. the current pump is a pond master 26 which is rated at 2600 gph and I have been told by members here that the pump is too large for my return line and that it does not allow the fuge to do a good job filtering because the water is moving too fast. right now that pump because of size and heat is an external pump. my question is do most people use an internal or external design for their return pump. I have a Rio 2100 that I am considering to use for the return. I figure that it will probably only do about 1200-1600 gph due to pipe length and I am also considering just using it internally but I am open to suggestions. I plan on taking the pond master and using it as a CL system. thanks for any help.