duct tape the leg on for a temp fix.
Alot of people do 3 days of darkness to kill off bad algae so I would assume no harm will come for a short while with no lights.
If it was me I would just do a temp thing to fix the light even it it was placing a brick or a book <depending how hot it gets> or hit home depot for a aluminum angle and hack saw it to size and screw it on as a leg. Just make sure you screw it to a spot that dont show when its fixed right.