The inner frame is used to hold the lighting above the tank and provide a barrier between the tank area and the lighting itself. Below is photos of the parts of the inner frame.
After being out of the hobby a few years I decided to get back in after a visit to Melev's website. So i decided to setup a smaller tank I had. It just happened to be a Hex tank. I wanted to used LED lighting so I needed a canopy to install the lighting in. So here goes.