Definitely. It might look transparent, but even transparent glass cuts light penetration by a very good amount, but the human eye isn't great at distinguishing differences in brightness.
If you got a manual DSLR camera and fixed it's exposure, took a picture of a white sheet of paper, then again through the "transparent" ball, you'd see a gray piece of paper, as the ball is cutting a lot of light out. It reflects light, refracts light, filters light and blocks light, so 4 different ways that ball cuts light to the chaeto.
Fragments of chaeto aren't a problem. They'll be pulled into the tank and eaten, and any that get caught on impeller shafts will die and turn to mush and dissolve.
