An optical blood monitor for use in a hemodialysis system operable to monitor at least one blood constituent, the optical blood monitor comprising: a blood chamber including a body defining an internal volume for receiving blood to be monitored by the hemodialysis system, an inlet for supplying blood to the internal volume, and an outlet for withdrawing blood from the internal volume; and an optical blood sensor assembly including a light source that emits light along first and second optical paths, the first optical path extending through the blood chamber to a first sensor and passing through a first section of the internal volume of the blood chamber that has a first thickness, and the second optical path extending through the blood chamber to a second sensor and passing through a second section of the internal volume of the blood chamber that has a second thickness, the second thickness being substantially greater than the first thickness, characterized in that the light source includes a light element emitting light about an axis, and wherein the first and second optical paths are disposed at an angle with respect to each other and are symmetrically disposed about the axis of the light element such that an intensity of the light emitted along the first optical path is substantially equal to an intensity of the light emitted along the second optical path, and wherein the body includes: a first wall disposed on a light inlet side of the body that is configured to receive light for optically monitoring the blood and a second wall disposed on a light outlet side of the body from which the light is transmitted to the first sensor and the second sensor; the first optical path extending through the body, the first optical path orthogonally traversing a region of the first wall, passing through the first section of the internal volume that has the first thickness extending from the first wall to the second wall, and orthogonally traversing a region of the second wall; and the second optical path extending through the body, the second optical path orthogonally traversing another region of the first wall, passing through the second section of the internal volume that has the second thickness extending from the first wall to the second wall, and orthogonally traversing another region of the second wall. a blood chamber including a body defining an internal volume for receiving blood to be monitored by the hemodialysis system, an inlet for supplying blood to the internal volume, and an outlet for withdrawing blood from the internal volume; and an optical blood sensor assembly including a light source that emits light along first and second optical paths, the first optical path extending through the blood chamber to a first sensor and passing through a first section of the internal volume of the blood chamber that has a first thickness, and the second optical path extending through the blood chamber to a second sensor and passing through a second section of the internal volume of the blood chamber that has a second thickness, the second thickness being substantially greater than the first thickness, characterized in that the light source includes a light element emitting light about an axis, and a first wall disposed on a light inlet side of the body that is configured to receive light for optically monitoring the blood and a second wall disposed on a light outlet side of the body from which the light is transmitted to the first sensor and the second sensor; the first optical path extending through the body, the first optical path orthogonally traversing a region of the first wall, passing through the first section of the internal volume that has the first thickness extending from the first wall to the second wall, and orthogonally traversing a region of the second wall; and the second optical path extending through the body, the second optical path orthogonally traversing another region of the first wall, passing through the second section of the internal volume that has the second thickness extending from the first wall to the second wall, and orthogonally traversing another region of the second wall. the first optical path extending through the body, the first optical path orthogonally traversing a region of the first wall, passing through the first section of the internal volume that has the first thickness extending from the first wall to the second wall, and orthogonally traversing a region of the second wall; and the second optical path extending through the body, the second optical path orthogonally traversing another region of the first wall, passing through the second section of the internal volume that has the second thickness extending from the first wall to the second wall, and orthogonally traversing another region of the second wall.