So a couple questions guys i am really looking to do this all at once so its less stressful on my fish. this was my game plan the tank is all hooked up and ready to go i am going to fill it with water from my RO
unit and was thinking of getting more RO
from the supermarket because it will take me forever to make 75 gallons of RO
water i will also put some of the water from the 45 but i really don't want to put all of it. i figured this was ok because the bacteria is really only present on the rock and sand. I want to put all the rock in the tank first that way the bacteria doesn't die. then i am going to put new sand in the new tank but i will take 4 or 5 cups of my old sand to seed the new sand bed. and then acclimate my fish. you think by doing all this in that order i will avoid any problems. if you guys see any flaws in my plan please feel free to inform me i want this to go as smoothly as possible thanks alot guys. (sorry for the long post) i also only have 4 fish so as far as spikes go you think i should be ok since its such a little bio load for a 75 gallon tank.