My tank is a 20g long (30"x12"x12"). I found an unrated powerhead at a relative's house but it was way too strong. My only sources of water flow at present are from the filter (Penguin 170) and indirectly from a Maxijet 1200 through the skimmer. What powerhead model(s) would be recommended for the tank, or do I not need anymore? Everything flows around the tank fine right now, but I imagine if I ever put more corals and/or LR in I may need additional movement. The tank houses one LPS and mushrooms, and a plethora of mobile inverts as well as a single fish at present.