I HAVE A 150GAL REEF READY TANK THAT I WILL START WORKING ON AND THE PUMP WAS ONE OF MY FIRST CONCERNS SO I DID SOME RESEARCH ON THIS. I AM GOING TO EXTERNAL BECAUSE IT WILL BE LESS HEAT ON MY TANK. THE PAN WORLD 50PXX IS MY CHOICE OF PUMP BECAUSE I HAVE READ AND HEARD NOTHING BUT GOOD THINGS ON THIS PUMP. YOU CAN GET THEM FOR $139.00 TO $169.00 AT MARINE DEPOT OR IF I AM NOT MISTAKING AT FISHY BUSINESS.COM FOR MAYBE CHEAPER. LOOK THESE PUMPS UP COMPARE THEN MAKE YOUR CHOICE I HAVE.