You could try using adhesive hooks on the ceiling or wall. They are strong enough to hold lightweight fixtures and won’t require drilling holes. Just make sure to clean the surface well before applying. Another option is using a tension rod across the top of your tank to suspend the light. You...
Hold off on the aloe and switch to a more balanced diet with hay as the base. Those deep cracks sound serious, pics would be a huge help for everyone to diagnose the shell problems.