tank upgrade cycle?

[SHADYreefer]

hi, I have had a 60 gallon up and running for a year. I now bought a 120 that was set up for multiple years. He had fish in it at one point but he got tired of caring for them and has had the tank running with just live rock for 3 months. I plan on adding my fish and corals to his existing set up.

Will the transfer of fish to an empty reef create a cycle?

as of now I plan on adding a few fish at a time over the next 30 days.

[fshaqrmman]

Did you put the old water from the 60 gallon into the 120?
Are you using the water that was in the 120?

I would believe that either way you will see a bump of NH4 and NO2 with the first week or two.

[SHADYreefer]

I will be using the water from the 60 with the water I was able to save from the 120 gallon purchase along with newly mixed saltwater.

[jerpa]

If the 120 has not been fed for lack of fish there may not be enough bacteria to cope with the bioload from the livestock in your 60. If you are transferring all your rock from the 60 also that should help reduce any cycle. As for the water I would do some hefty water changes in the 120 unless the previous owner was keeping up on them. This will also allow you match the new tanks water to your current parameters. Adding the water from your sixty would help even out the differences in water parameters. However it won't do much to stop it from cycling as the bacteria you need to establish aren't free floating in the water column. They stick to the rock, sand, etc.

To test the bacteria level in the new tank you could put some fish food in there and monitor your ammonia, nitrate, and nitrate levels to see if you get an ammonia spike. If it checks out then you could slowly transfer your livestock over. I would do it slowly over the course of a few weeks. One fish at a time at first while keeping an eye on your parameters. Then you will have a 120 and can keep your rock in the 60 and have another tank cycled and ready to stock....