Will I screw things up by doing this?

[jimi thing]

I know I have asked this question here before but got a few different opinions about it.
I have a small 12g eclipse with about 20 or so lbs of LR in it. The tank has been set up for 6 months and doing very well.
My question is can I use the water, rock and a couple cups of my sand (to help seed the unseeded sand) and add them to my new 30g cube w/10g sump will I have any problems with the tank going into another cycle?
I will be adding about 27g of uncycled and 12g of cycled water from my little tank.
going from this

to this

I'm sorry if I've asked the same question before, I just don't want to kill everything.
Thanks for any advice and help that you can give.

 

[nalbar]

Your post is not all that clear on what you intend to add to the new tank.

If you add new live rock, you will get a cycle. If you add new sand (not live sand) you will not get a cycle (I add new sand to my tank occasionally).

Even if you take the rock out of your old tank and move it to the new you risk a small cycle if the rock is out of the water for very long (let's say 5 minutes).

Even moving the sand from your old tank can create cycling issues, because you may disturb something that is buried in it.

The typical 'safe' way to switch tanks;

New live rock and new sand go into the new tank.

Allowed to cycle

Rock and sand from old tank added.

Corals added.



nalbar

 

[atvdave]

You shouldn't any cycle at all. If you do it will me a very small one.

It's best if you can get the other tank going first to help get the ball rolling.

 

[cashman95]

I would probably put some of your Live rock in the new tank along with a cup of sand, freshly made salt water and give it at least a week or two to get things going. Then maybe transfer more of the rock and eventually fish and corals last. Your new tank will have to cycle no matter what...and it is best to move the system over slowly.

 

[jimi thing]

OK, Thanks for the help guys. I guess I'll have to go out and buy some LR and start the cycling process again, I was hoping not to have to do that as money is a lil tight right now.