So I've done this many times in the past, upgrading to a bigger tank. Set up new base rock, stabilize water in the new tank for a few days, then move everything from the old tank to the new after acclimation, (re-acclimating to lights is usually necessary too). Never had a re-cycle or anything, though only once did I move the substrate.
But I've never done such a drastic change. In this case, I'll be moving the contents of my 9 gallon to a 70.
I would think that it'll be fine, but I am anticipating a mini-cycle simply due to the volume of water. My plan is to also move the sand from my 9 to the refugium in the sump after a good salt water wash. The tank is only 6 months old, so I don't expect trouble from the sand, but the wash will be a little bit of insurance.
So I'm wondering if I should do anything special for such a drastic size change?
But I've never done such a drastic change. In this case, I'll be moving the contents of my 9 gallon to a 70.
I would think that it'll be fine, but I am anticipating a mini-cycle simply due to the volume of water. My plan is to also move the sand from my 9 to the refugium in the sump after a good salt water wash. The tank is only 6 months old, so I don't expect trouble from the sand, but the wash will be a little bit of insurance.
So I'm wondering if I should do anything special for such a drastic size change?

