Coming along nice, I like the rockwork.
Seems your sump doesnt have any baffles that force the water down, or can I just not see them in the picture?
Anyways, you can add a couple more baffles pretty easily. Just find some cheap acrylic sheets at home depot, cut them to size and wedge them in place (you can silicone them in if you want, but if they fit well enough you dont need to)