upgrading from 90 to 180 reef tank

[parmoffitt]

I have a 90 gallon reef tank up and running for over a year and thriving with no problems. I am wanting to upgrade to a 180 gallon tank. My question is could all the water, substrate, LR and fish be put in the 180 gallon along with new substrate, more cured rock and new water added and the tank not have to cycle? I asked the LFS and they told me there might be a slight spike but they felt it would be o'k to start up the 180 gallon that way. I have reservations and wondered if I am flirting with disaster and maybe I should start over from scratch letting the tank cycle without fish a corals. I had hoped that maybe by putting everything from the 90 gallon into the 180 it would prevent the cycling process?

 

[jester805]

I think you might see a slight spike (mainly from kicking up the substrate), but you should probably be ok. When I upgraded from my 29 to my 75 I went from crushed coral to live sand so I can't say for sure.

 

[badoleross]

Most of the threads I have read regarding a move like this is to use your live rock but to get new sand and use a small amount of your old sand to seed the new stuff. From what I understand, disturbing the sand bed will give you a huge ammonia spike that can kill off everything in your tank. I have heard stories of peopke just rearranging all of there rock and disturbing the sand bed and losing the entire tank.

 

[gold strip]

You will get a spike. I made the same move about a year and a half ago (90 to 180). You are doubling the volume and your rock and sand have settled so when you stir it up you will have trapped waste being released and anarobic (Sp) bacteria being exposed to oxygen and dying. There is no way to avoid it.
I would use all the rock and sand unless you have a deep sandbed. Then I would use the top 1 inch of sand in the new tank and take the rest of the sand and rinse it very well and let it dry. You can use it later to replace sand that disolves or gets filtered out.
Good luck.

 

[deansreef]

do not reuse any of the sand, you should maybe go bare-bottom.

 

[parmoffitt]

Thanks for the replies. The LFS said they would take back the 90 gallon and sell it on consignment by making it a display tank. Would you let the fish go back to the store and let the tank run without them?
I never heard that changing around your LR could cause problems for the tank. Thanks for the input.