well the tub is not completely blacked out so there will be a difference between day and night.
others here have kept them in complete dark with no adverse effects.
I will only be keeping young snakes in these. I'm going to make a rack when i find the right size and quantity for adults.
I feel they would feel more secure in these for there first year with me. They will be in much larger standard tubs when they are breedable sizes.
Jim