I did it very similar, except I filled the PVC pipes with sand before I fully closed them and glued them together. That makes it much heavier, it wont float and it's hard for any fish to "push" it around. Then 2-3 suction cups on each side and done. Also, I made mine about 5cm (2 inches) above water level, because I once had a ray that went over the divider all the time back when I had made a divider that was as high as the water level was.
