It looks right. The only place you'd see the flow is the 2nd to last baffle, and the flow is spread over the entire length, and that looks like a good sized sump. First, test by removing s bit of water so you can see the flow, or add some food to the middle chamber of the sump to see the flow. 2nd, I'd add an elbow to the input of the pump to draw water from lower in the return section. The water level in the last baffle section and the return compartment will always be the same as it's an under flow baffle. The water level in the rest of the sump is dictated by the 1 over flow baffle.