In my experience in the saltwater hobby, eggcrate is one of the most valuable and versatile materials to have around. Here's another eggcrate DIY project. DIY Coral Frag RackMaterials
2. Magfloat or other brand of magnetic aquarium cleaner
4. Super glueDirections
1. This DIY is a piece of cake. Simply cut the eggcrate to the dimensions that you wish your frag rack to be.
2. Glue the "wet" half of the Magfloat to the base of the eggcrate, and let it dry.
3. Now just put it inside your aquarium and secure it with the "dry" half of the Magfloat on the outside of the glass in whatever position you'd like.