I haven't seen any difference in efficiency due to the transparency of the composter. It's typical to see larvae up against the composter walls at all levels. They tend to rest below the surface and they don't seem to be bothered by the light. I can cause resting larvae to move by shining a flashlight on the them, but they aren't bothered by ambient light. Of course I keep the unit in full shade, but if direct sunlight hit the wall the larvae could easily migrate a short distance to avoid it.
When I chose a clear container I did it based on the idea of mimicking the natural environment of wild BSFL. The drainage system and flushing method came to me when I considered the rinsing effect of rainfall. It's very unnatural for a concentration of larvae to be contained in plastic, and passing water (and then also air) through it has greatly reduced issues that would otherwise be a problem.
My initial thought about a clear container involved allowing UV rays into the compost, like in a natural setting, however plastic blocks UV so that benefit is missing. In theory a glass container would be better. Although I didn't consider it during the design phase, the clear plastic is excellent because it allows us to study the larvae and also conditions below the surface. For example, it's good to be able to assess the amount of air space in the compost with a quick glance. This can inform the user that it might be time to do a flush. You can also see if the liquid level is high, which would indicate the need to drain if you're keeping the valve closed, or a blockage if you're keeping it open.
Anyway, thanks for your comments. I've been distracted by regular work lately so regretfully I haven't been giving BSF much time.
