I have used Pan World Pumps since 2003. CB Pets used to get them and then I ordered them online, Louis can now get them through BRS. My favorite is the 50PXX - 1110 GPH @ 90 watts. And you will hear the cooling fan if you listen closely. My second favorite and I use it as a day time pump to add more circulation to my 300DD is the 40 PX, 480 GPH @ 45 watts and no fan so no noise. I also used the 100 PXX 1270 GPH @ 130 watts but it was noticeable, not irritating but you knew you had a pump running. I love using the two pump system because at 10 pm when my second pump shuts down my over flows get much quieter plus a much gentler flow through my tank and then at 8 am we are back to full force.