I'm setting up a 120 gal . I am going to run the plumbing to the basement where the sump/ fuge and a frag tank will be set up. The return will be approx 15 foot head with one check valve and two 90 degree bends in it. I'm going to use flex PVC. Total water volume will be 170 gal. I thought of using an Iwaki but what size should I go with? Is there a better pump for this application? Any advice would be appreciated