Now what....

[henryd]

Biffer..
My substrate is about 2" deep and is a mix of arrognite and live sand. When I had the fish only, I used Southdown but pulled that out and put this mix in. LFS did not have a sea hare this weekend but I will keep checking back until they do. They are going to set one aside.

 

[Bifferwine]

Substrate can cause algae problems, but it's usually crushed coral that leads to problems. It doesn't sound like your substrate could be the cause of any of this.