Hi, just set up a TIRGON 240 corner unit tank, everything is working ok but i have a question on the pump. At the moment it is under water but still working and pumping water back into the tank, should it actually be out of the water though? I tried it out of the water and got a lot of splashing and its also quite noisy.? My other fear is that because its under water is it possible for my smaller fish to swim into it or would the pressure be too strong for them to do this.