I wouldn't add any more LR, it looks good and i think people put to much in. As for getting the damsel out, if your lucky (and fast) you can get him when he comes to the surface to feed. If not, the best way to catch them is to chase it to one end of the tank, move the rocks so you can isolate him using a window screen. Then, once trapped remove the rocks in the screened area. That way hes in a small space with nowhere to hide.