I am using a cobalt maxi-jet with sure flow 2100 gph upgrade kit with sure grip 100 magnetic holder. It was so powerful that I have to take it out of the tank until my Jardini got a little bigger. The 1600 propeller is also good but the 2100 pushes a lot of water. It was a bit noisy at first but that was b/c I did not set it up right. After taking it apart and re-assembling it back together, everything was good to go. I am very happy with it.