in a 24 gallon with 72 watts, eh? first off, a 24 gallon is not a nano, and second off, 72 watts over that tank is crap. I would say that 96 over a 10 gallon isnt good enough either. BUT, with some immense lighting, and maybe a 15 gallon tank, with pristine water quality and the right care, i guess its possible. That is if you want to baby the thing. Even then, a clam can become the size of the nano in time, so i wouldnt do it anyway...