Making our own hermit crab tank?

Question

My dad and I are working on making a hermit crab tank. We want to make one third of the tank with coconut fiber, one third play sand, and one third a saltwater pool. We want to make a wooden base and use copper piping with a heater to warm the pool. We will then lay cement over the piping and make a cement slope so the hermit crabs can climb out. We want food and both fresh and salt water dishes on the sand side, and shells, grapevine, and coconut huts on the coconut fiber side. We want to keep the panes of glass on the side in place by sliding them into aluminum rods in each corner. Of course there will be a screen on top. Does anyone see a problem with any of this?

Answer 1

yes all of it

Answer 2

instead of making all different types of  substrate make two, coconut fiber and the pool, make the pool with fresh water not salt water, scatter the shells all around not just in one spot everything else sounds good if you now what your doing.