A cartridge-style flow sensor for sensing fluid flow. The includes an exterior, interior, head, base, a circuit board, and first and second ports. The first and second ports permit fluid to flow into and out of the interior. A Hall Effect Sensor in the interior detects the number of revolutions of an impeller. An electric coupler interfaces with the sensor and a transmitter for communication of the revolutions of the impeller to a controller. The controller determines the rate of fluid flow in a conduit. The controller automatically issues a command signal to a component of a hydraulic system to alter the rate of fluid flow in the conduit. The cartridge hydraulic flow sensor is easily and releasably engaged to a cavity of a hydraulic circuit manifold.