switching tanks

I have a 30G tank with 20G ruge right now that has been running for a year and a half. Very stable.

I bought a 75G tank today (for $65 ;D) and will be putting the 30G in it. Will I need to put my fish in another tank for a while to get the 75G up and running? All the LR, sand, and everything is cycled, and full of life. But with the new tank, I will be adding a lot more water to the system. Will this be too much of an adjustmant for the fish in the tank?

Currently the 30G has
2 false percs
1 yellow stripe maroon
2 Bangai Cardinals
1 Yellow Watchman
1 Blue Damsel
1 Porceilin Crab
1 emerald crab

I will be adding more LR to the 75G tank, but it will all be ready to go. Been sitting in the 90G fuge for about a year. Will anything harm the fish by putting everything into the 75G tank?
Thanks,
Ty

 

I have a 29g and I working on my 75g build. When I switch the tanks I plant to:

-only add dry rock in the new tank - no live rock[that is not cured]
-use dry aragnoite sand. This will be new sand(not from 29g), but there is no life it it yet so it should be ok - maybe give it a week if you are worried about a cycle.
-add all water from 29 into 75
-put rock in
-corals
-then add fish last

 

So basically what I am saying is going ahead and switch the tanks over...

 

I switched tanks in feb, went from a 46 bow to a 65 reef ready, I used a bunch of big buckets be prepared with new saltwater to make up the difference in tank sizes. Pull out saltwater from your tank and put your corals inverts fish in there. Pull out the rest of the water and than pull out the sand and put it in buckets. Move the old tank put the new one in it's place and reverse the order. You WILL have a huge sandstorm that will take a week to go away and a mini cycle but you will be fine. Hard part is rock placement when u cant see thru the water. Good luck. Bty make sure new water is at good temp and salinity