First, if you move a lot of old sand to the new tank all at once I think that will be a problem. Maybe delicately move just the very top inch of your sandbed. Is the question whether you can move everything from one tank to another and avoid an ammonia spike? There are just so many variables on how you would do that. I've moved tanks before and set them up again with no problems. I did not disturb the sand bed at all and saved almost all the water. My concern would be 100 extra gallons of water and how much denitrifying bacteria you'll lose. Remember any amount of ammonia will kill. Actually, I am planning on moving everything out of a tank. I'm moving only a small amount off the top of the old sand bed, but I'm not also adding that much water. There's just so many variables? You always hear no more than a 50% water change. ?
