Is this a bad idea?

[Aquattro]

I might use the water from the existing sump (it holds about 60 gallons) but the sand is new, rock is new but partially cured/seeded, some existing rock will move over eventually.
Fish load is medium for 180, 15 fish total. 5 butterflies, a tang, a wrasse, 4 clowns and 3 damsels. Pretty sure I'll need to have new water on hand in case of a spike.