I am so glad I posted this. I run dual rio 3100 on my 120g reef tank it does great. I am going to buy two sub pumps. In debate between the rio 32 hyper flow or mag drive 18, rio pushes a little more gph and a little less wattage than the mag drive plus $50 cheaper. I have used rio 2100 and 3100 for years and no problems (knock on wood)