Switch from one tank to another?

[21chip21]

The big move!
If you use the same substrate and same live rock. and a lot of the older water. Will the tank still spike. Im going from a 72 bow to a 90 gallon over flow tank. Iv got everybody in a 55 gallon now.
and i got want to kill anyone of my buddies.
Anyone done this with no problems.

[datablitz]

with your sand and rock, you should be fine, even if you dont end up using all your water.

i just re-did my tank, fully drained and emptyed, to drill it, i replaced the sand and rock, and used %95 fresh RO salt water, with no issues.

[WingnutSr]

I just completed a tank swap. When I got the original tank to where there was only the sand remaining, I scooped it into all a bucket. But when I went to put it into the new tank, the closer I got to the bottom of that bucket, the nastier the water/sand looked. I had planned to re-use it all. But the way it looked (gag), I just couldn't do it. So, a quick run to Home Depot, and a 20 lb bag of play sand, which is really cheap, and I was all set.
And the really good part, NO spike of any kind!

[datablitz]

yea, i forgot to mention that i pulled out and rinsed all my old sand, in salt water to get most of the debris out, and re-used it.

[21chip21]

Well that sound good so far. Im just put my home made sump with three chambers in it. I made a 30 gallon sump for my 90 gallon. I hope i never need to take the sump out. I had to put it in under the main tank and remove the center board to get it in.
Iv got a half a tank of RO water and salt in now!!! Im almost there. New Tek T5 light should be hear wed. Everybody that i throw in my 55 gallon seem to be doing well. Im going to fill and let it set for at least a day. Then try it. Thanks for all the good news..... So far.