Wouldn’t it be easier to just use your live rock in your existing system in your new setup and avoid a cycle altogether?
I know this doesn’t answer you question, and I don’t know your circumstances, but if you can, that is what I’d do.
Great, they you can absolutely do it. Bacteria only lives on surfaces, not free-floating in the water, but I’d still fill the new tank with about 2/3 old water. There is plenty of surface area on your live rock and it won’t matter that the new equipment is not “live.”I was wondering if that would work..... new tank is 200 gal, i could drain my 360 enough to fill new tank completely , put in existing rock, only issues... new sump, new skimmer, new plumbing... nothing " broken in " do you really think doing this would avoid " cycling " tank ?
Bruce
Great, they you can absolutely do it. Bacteria only lives on surfaces, not free-floating in the water, but I’d still fill the new tank with about 2/3 old water. There is plenty of surface area on your live rock and it won’t matter that the new equipment is not “live.”
When initially transferring, To be sure to avoid a cycle, I’d use more established live rock from your 400 in the 200 than you actually intend to use long term. After a month or so, take out what you don’t need.
I am very confident you won’t have a cycle going this route. I’ve done similar in the past with upgrades. It will be even easier with a downsize.