Replacing this lid seemed like just the project to introduce myself to the laser cutter they have at our local techshop. It turned out pretty well, so I thought I'd post something.
I wanted a lid which would slide around easily for maintenance and feeding, but still let in plenty of light. The design is pretty simple. It consists of a grooved platform which rests on the glass rim and rear wall. The platform routes around the light supports so they're free to move back and forth on the rim.
The lid is designed to sandwich and support a panel of random mesh material. I've been playing with bird-netting as well as acrylic with a matrix of holes. I think the acrylic center panel is going to hold up better, at the expense of cleaning the salt off it periodically.
I brought in some sheets of 1/4" acrylic and cut the design out:
The laser automatically gave the pieces a fire-polished edge, and the etching came out well too!
Here's how it sits on the tank (without any mesh installed in middle).
