I built a simple diy mesh cover w spare wood I had laying around. Aesthetic wasn't an issue. One of my two eels must have jumped out of a 2-3" gap I have near my overflow box that wasn't covered. I heard eels likeed jumping but didn't know how good of an escape artist they can be. I can easily modify the top by adding a chunk of wood to cover that gap, my real question is, if a weighted top is necessary. It has more weight then the diy metal top...wanted to hear other's experience w this.