Abstract: A baffle includes a conduit and a flow director flap portion. The conduit includes, at its front, a curved wall generated on an axis running the length of the conduit. One pair each of two pairs of angled walls, extending the length of the conduit, is attached to each side of the curved wall by a free edge of one of the pair, the other edge of the pair being attached to a wall for mounting, the wall having holes for mounting the baffle to a concrete septic tank wall, over a port in the tank wall. The angled walls are preferably perpendicular to each other and to the wall for mounting, the two walls formounting being coplanar and at the back of the conduit. The flow director portion includes two angled walls, one is for attaching the portion to the back of the conduit, the other extends over the end of the conduit and has a surface that is further from the curved wall than it is from the paired walls when the flow director portion is attached to the conduit.