[Octoman]

Stace,

I see no problem in adding the fuge after the 72 cycles. However, I would not recommend adding the sand as is. You should use a cup or two to seed the sand in the DT and keep a cup to seed the fuge, but the rest should either be discarded or rinsed clean before reuse. You don't want to risk introducing nasties into the water from the old sand.

The only things I can think of that would cause another cycle with the fuge is if you added uncured live rock or live sand when you hook it up.