Oh no the bins are entirely closed, except for airlock. Just thought of using the blankets for blocking the light. But now I know I don't have to. Thanks.
Wow- I've always covered my carboys to keep them from getting light struck. Wines, particularly white wines, should be protected from light, too. They won't "skunk" like beer (due to the hops oils) but will change color. I store wine in the basement in the dark, and I keep the carboys away from light, too.