Abstract: A method for detecting changes in the rate of discharge of fluid from a well bore. Firstly, providing a flow nipple having a first end, a second end, and a flow line connection extending substantially radially from the flow nipple intermediate the first end and the second end. Secondly, providing a drilling fluid treatment tank. Thirdly, providing a flow line having a first end and a second end. The first end is connected to the flow line connection of the flow nipple and the second end to the drilling fluid treatment tank. This creates a flow path for drilling fluids from the flow nipple along the flow line to the drilling fluid treatment tank. Fourthly, providing an elongate antechamber adjoining one of the flow nipple, the flow line or the drilling fluid treatment tank. The elongate antechamber has a first end and a second end. The first end is positioned in fluid communication with the flow path.