Depends on the setup like if you are just hanging some frags in your standard mixed reef tank or in a dedicated frag system, but frags can grow unobstructed in all directions, have good flow, access to nutrients in water column, efficient use of tank space, get reflected light all around if there is open sandbed, and are protected from lots of predators, irritants, algae, detritus, and sediment.
At first I misunderstood, but I think our specific challenge will be to select non-plastic materials to use in an existing design. I thought we were designing a new structure or method of suspension. But we can still do that for ourselves. So I'm thinking students will think about materials, find out about density and buoyancy to meet an aspect of the challenge requirements, research what materials indigenous people used for floating applications, research some materials, test materials in containers of saltwater to learn the effect on water chemistry and what happens to them after being immersed for a long time, if they are safe for our tanks they could put materials in and see what nuisance life grows on them, then maybe make some little models to place in our tanks with frags. The whole time we could also be growing out suspended frags that are not on a structure just to try it out and compare to mounted frags.
Not sure. This is all ideas so far. We have other stuff to do in class and I'm not quite sure how to manage this project or if I need to try to set up another tank (in addition to the coral QT I keep meaning to set up and a tank with light issues, haha). I will speak to our shop and maker teachers next week since they are used to facilitating projects. Plus, I will need the new shop teacher's tools and services, heh heh. Gotta plan out materials I think kids will think of or I will guide them toward so I have some on hand when we're ready to start.