The water distribution / turbulence was maximised by the multi inlet feed to the tank, plus the power heads working randomly via a 4 port wave controller. The weir removes surface detritus,  maintains a constant water level and has the safety of the overflow pipe if the return is blocked. Return water is filtered by the Reef 500 unit, mechanically and biologically, and sterilised prior to return to the tank. Water temperature is maintained via the external chiller unit, the sump heater and the dual hood fan units (without which the hood gets very hot because of the halide units). Electrics are sectioned off from water - just in case!