Hello and thank you for your inquiry.
There is a lot more information that we would need to get from you to help assist such as water parameter (temp, pH, alk, calcium, mag, etc...), how quickly stuff died off, how often you change your water, changing bulbs, etc...
I would suggest sending us an email (firstname.lastname@example.org) so we can go over more information to try to help solve what is going on within your tank.
Looking forward to hearing from you.
Marine Depot Customer Service.