How much water do I need to save when I move my tank?

[flipper263]

Hey there!
Been a while since I posted so here is my situation.
I have a 120 reef tank and just purchased another 120g tank. The new tank is an in wall tank and the 'old' tank will become my sump for the new one.
Here is my problem...I don't know how much water I need to save to avoid a cycle in the new tank. We currently have the new tank full with a small 10 gallon sump just to make sure there were no leaks in the system. I have new sand in the new tank and don't plan on moving the sandbed in the old tank (aka new sump).
If I keep all the water in the existing tank, (save it in pails, move the sump, then fill the sump with the 'old' water) will that be enough cycled water to keep the reef alive and well?
Thanks for any help
Brenda
P.S. I have been taking pictures of the process and will post some when we are done if anyone wants to see them.

 

[lepete]

You wont start a cycle again. You can only start a cycle if there is die-off creating a large spike of ammonia. So, make sure your new sand is clean.

 

[flipper263]

Thanks for the reply...
The new sand is clean and in the tank with 120 gal of new salt water. Won't there be some dieoff if most of the water is new?? Some of the rock will go straight into the tank and the rest will go into the sump with the water from the existing tank...just wasn't sure if that was enough...I don't want to make the change too quickly (though I am dying to see the new tank completed) and at the same time, I don't want to do it too slowly and create problems for my existing tank by moving rocks just a few at a time. (that would create dieoff wouldn't it?)

 

[lepete]

Yes, there will be some die offs. But it is minimal and the bateria on your current LR/LS should handle it fine. Your new water will dilute the ammonia even more.
But, get more opinions...

 

[flipper263]

I'm trying to....but as you can see...not a tonne of replies...anyone??

 

[stanlalee]

when I moved I saved enough water to submerge the substrate (in a bucket), enough to bag the livestock and enough to submerge the live rock (in buckets). I only moved 30 minutes away so I just pushed airtubes into the buckets until the tank was set up where I wanted it. As for using the water I actually used NONE other than residual that was with the substrate and rocks. I tested the pH and salinity of the new water which was virtually the same as the old water. reacclimated the livestock and no recycle. no losses fish nor crustascean. I didn't use any new substrate though so there is probably a slight added load that I didn't have.