That's a little better, but you still have the issue of using a submerged plastic canvas screen. Essentially that is a horizontal scrubber, which are not very efficient due to water flow characteristics. That's why the old style horizontal scrubbers were either dump bucket or surging. In both cases, the purpose was to cause very turbulent water motion over the substrate. With a static screen/box and static flow, it's going to be hit or miss. I guess see how it goes, it might grow enough to do some good, might not.