I know nothing about aquariums, but it's something my husband has always wanted, and while he is overseas, I purchased a Cade 1200 S2, and am attempting to set it up myself as a thank you for everything, for when he gets home. I did a bit of research and have plumbed it, and am in the process of filling it with water. This is where my total lack of knowledge comes in, I can't work out how water enters the weir so it can enter the main downflow pipe, I thought the water would fill the weir through the lower inlet to a level equal to the water level in the tank. I noticed the weir is separated from the lower and upper inlets by a glass wall; but I'm not sure where to go from here. Any help in this matter would be so much appreciated.