Tank has calmed down now, he hasn't left any more deposits.
Brian, if I don't uncover Tank's house within a few minutes after 7am, he starts banging around inside to try to remind me to uncover and put on his lights. So, trying to keep him the dark is right out!!
You could try reduce light cycles/cover up windows etc and gradually reduce the light cycles. If that is ineffective then you might be able to trick his little brain out of mating season by doing a total lights out for about a week.. cover cage no lights at all.