This is the external pump I ran on my tank before I had to redo the plumbing. There is absolutely nothing wrong with it. I am not 100% sure what the GPH and max head are but I was getting the same amount of flow from my return as I as from a 1400gph powerhead. (that was restricted down to 1 inch pvc) Pump would be much better suited for a "closed loop" on a smaller tank or a really big tanks return pump. PM me with questions of for more pictures, thanks.