my bullet proof divider system is a little strange but here goes
you will need plastic egg crates and go to rona or homedepot and get some copper pipe insulation (basically pool noodle only smaller) cut the crate so it will just fit , slide the (pool noodle)copper pipe insulation over it and shove it in place,
if you cant make the crating fit or its in between one full square i have success with those cutting boards at the dollar store.
i know it sounds strange but hey, nothing going through that, however when not using crating it does f up the water flow between sides
hope it helps, worked in the past for me with my red devil... and he is a class a jerk