Changing from a 55 to 75 gallon

[Waterwidget]

I was just wondering. If I change from a 55 gallon to a 75 gallon does it still need to be cycled if I take the live rock and water from the 55 and use live agronite from petco. The bag says no cycling need just add water and I will probably take about 30 gallons or so from the 55 and fill with the premade ocean water by catalina company. It would make sense to me but just covering the bases. I will pobably ditch the canister filter and use a sump sytem. I found a good complete system at aquariums direct and that should fill the bill.

current system is
55 gallon tank
canister filter
aqua c remora pro hob
55 pounds live rock
40 pound argonite sand about 2 inches worth
coralife aqualight pro system
2 power heads for circulation
1 9w uv sterilizer
1 purple tang
1 curlycue anenome
2 gobe firefish
1 cleaner shrimp
1 perpmint shrimp
1 coral beauty angelfish
1 crocea clam
14 snails mostly turbos a few I got at the lfs but one I can't identify big though and slow moving. Shiny shell.

[Ninong]

You don't need the fancy, supposedly "live" aragonite from Petco. Any aragonite will do. It's not really "live" anyway. It just has semi-dormant bacteria in the bag. The same sort of bacteria that you already have in your live rock and the same sort of bacteria that would show up in your sand bed whether you paid for it of not. But that's up to you. It won't hurt. It's just unnecessary.

If you move everything from your existing tank to your new tank, the new tank will go through a period of stabilization but it shouldn't have any ammonia spike or nitrite spike because chances are that there will be virtually no dieoff at all.

Try to save as much of your existing tankwater as possible to transfer to the new tank.

Good luck!