I was going to go with Rio 1100 and Rio 600 units (2 a piece) and set them up throughout my tank. I was hoping to get a lot of current across my 72g bow front. I was thinking of buying one of those wave maker surge strips. I have heard that Rio units click when turned on and off. That would drive me nuts every 30-60 seconds! ;D Do the power heads need to really move? I was going to install the smaller flow unit in areas that might be blocked and/or build them into the live rock wall (maybe I should use 2 less powered units also?). Then use the larger 300g/h units on the front of the tank- where there is much more water vs live rock wall (one on the top, one on the bottom of the tank, mounted on opposite walls). Do those units click? What other units should I use? and $19 and $13 respectively they sound like a great deal.