Swapping tanks, do i need to cycle again?

[netjerk]

I have a 30g and just bought a AP24 and will be moving the live stock. Can I just use 50% of the old tank water and the live rocks and then put the coral in with out cycling since I'm using the same rocks and water?

[stevelkaneval]

i moved from a 36 gallon bow to a 20 gallon long, i just swaped tanks no cycle. i just watched my params very closely just incase but nothing happened. i rinsed my gravle really good and used maybe 60 of my old water. i hade to give away like 10 lbs of lr though.

[zma21]

Moving the water will be pointless as it holds little to no beneficial bacteria.

You'd be better off just making fresh water and matching it to the specs of your current water.

Acclimate your livestock like you would if you just brought it home from the LFS.

[GoingPostal]

I'd just mix up all new water and move everything over after the sand settles down, I've moved three nanos a few times now and I just throw everything in buckets while I add the sand and water. Then put everything back in, as long as the rock isn't out of the water an extended period of time you should be fine and my lps/softies have never had a problem being tossed into fresh water, no acclimation at all.

[Agu]

I use as much of the old water as possible when moving a tank. Although known parameters can be matched there are the unknowns we can't match. There's enough stress moving fish/corals from one tank to another without adding another variable.

You don't mention substrate. I won't move a sandbed because too much crud gets released when removing the rock. After everything is moved I will pick through the old sand for every critter I can find to add it back to the new tank.

As pointed out you should have little or no cycle.