New tank

[Soldja12]

If I purchase a tank from another person and keep their water will I have to cycle it? Mind you, I have a 90 gallon already and I am setting up a new 80 gallon frag tank. Could I take some of my live rock from established 90 gallon tank and media with pre existing bacteria?

 

[Spare time]

The water is not a good source of the bacteria. There will be a mini cycle no matter what as stuff will die in the transfer process. You can use your old rock and media but if you want to make the frag tank pest free it may be best to not do so. If you don't have pests, take some bio media and a bottle of bacteria and use it to seed some bioblock like marinepure or brightwell to be your filteration. I feel like rocks get in the way when making a frag tank.

 

[BayouReefer]

You can keep their water and you won’t need to cycle your tank but don’t disturb the sand bed in the tank. I would use roughly 75% of the water from the tank and use your existing live rock. The live rock is more important than the water.

 

[foxt]

As others have said, moving the water won't do anything for you in terms of cycling the tank. And either don't disturb the sand bed, or rinse it first (there is a great thread somewhere on R2R about rinsing a sandbed).

Moving the rock will work, although it might bring hitch hikers with it that you wouldn't want in a frag tank - your call on that one.

As an alternative to moving live rock from an established tank to a new tank to seed the biofilter, lots of people use sponge filters. You let it run in the old system until it is seeded, and then move it to the new tank carrying the bacteria with it.

 

[Soldja12]

That's what I thought. I have some rock in my sump and some ceramic pieces that I use as well. With those and my skimmer in my display tank, I think it will be fine. Btw i have 2 skimmers in my display so

 

[Soldja12]

The tank that I am getting does not have sand so there is no worries of disturbing