I have a mini reef 150, and there's a constant trickling noise coming from the overflow box. There's a durso standpipe and a return pipe in the box, I'm not sure if the trickling is coming from the water flowing into the overflow box or from the water draining through the pipe, but the sound goes away when I raise the water level in the overflow box, until it drains and the noise starts up again. Does anyone know a solution to this? Thanks. I can also post a video if needed.