filling a new tank

[Kevin34]

i am breaking down my 125 and setting up a 55g frag tank. if I use mostly water from the 125 to fill the 55 will the tank go through a cycle? there will be no fish in this system. only corals. and not many corals to start. just a monti cap, a couple acros, some rics, one acan colony, and a maybe 10 zoa frags. i will be transfering some LR over to the 55 also. there will be about 100g total in the new system (55g frag tank and a 55g sump/fuge) so what would you say a good ratio is for old tank water to new saltwater. like 60g old/40g new? has anyone set up a tank this way before?

 

[cparka23]

The cycle seen with tanks comes from decaying organic matter, which isn't affected very much by the water column. LR is where the bulk of the biological filtration will occur, so you should be fine if you're transferring rock from an established tank.

 

[cveverly]

I always seem to get a mini cycle when I change tanks. I suspect it is from disturbing the live rock and exposing areas that have been buried in the substrate. I agree with cparks23 about the water column. It should not have much affect.

 

[AZDesertRat]

Colonizing bacteria that convert ammonia to nitrites and nitrites to nitrates are not free swimming in the water, they live in the rock and the substrate. Using old water is not much of an advantage. I would start with new saltwater myself so there is less chance of transferring anything less than desirable from the old to the new. The rock and corals will have the bacetria you need.