I've tried to understand similar posts but I'm easily confused and not the most practical of guys. Basically,I have a steady trickle of water coming out of the oveflow pipe at the front of my house. In the cupbard by the loft I have 2 tanks. The larger one is about 20ins high and has a water level of about 16 ins.It feels like it is lapping over the overflow outlet. It is a bit hard to see what is going on because there is only a clearance space of a few inches between the top of the tank and the cupbard roof. The smaller tank is about 12 ins high but the water level in here is only 3 or 4 ins. I thought that maybe if I dropped the level of the ballcock in the big tank,that this might solve it though it is difficult to get at . Am I on the right lines?