I wanted to upgrade from an Eheim 318 GPH pump for a cooling application. I tried three pumps – Vivosun 800, Sicci 715 and this. While the first two underperformed their rated GPH, this WaterRebirth actually pushes 1500-1600 GPH through a 120′ generally level circuit to cool my greenhouse with swimming pool water through a heat exchanger. This pump is silent, smooth and powerful. I have to thank Amazon for their return policy, as not all vendors are as accurate as WaterRebirth. Thanks also to WaterRebirth for making a high quality product and representing it fairly! I now trust this brand.