This is an interesting way to flip a classic science experiment into a functioning addition to a fish tank. It makes a beautiful cool display!
Be certain if you do this to have plenty of water movement in your tank or the water in the suspended area could become oxygen deprived.
There really should not be any issues if the tank is definitely functioning previous to including the new compartment.
You might also need to put a wide base of some sort below the supports so the additional weight is spread over a larger area and you will not risk cracking the bottom of your tank.