Moving tanks - cycle requirements?

[houstonhobby]

Everyone,

I currently have a 90 gallon tank with two 20 gallon refugiums and one 20 gallon sump. All of these tanks have live rock in them to one degree or another and the refugiums have cheato and green bubble calerpa, plus pods and assorted animals that apparently rode in on the macro-algae (including one brown crab that is now about 1 inch in diameter).

Sometime in the future (already have the tanks, need to build a stand and get some equipment) I am switching to a 210 gallon tank, using a 125 gallon tank as the sump. I will keep the two 20 gallon refugiums and maybe hook the existing sump up as a third one.

Because of space requirements, the switch has to be made in one day. I empty all the stuff out of the old tank and sump, probably take the live rock out of the refugiums, and put all that stuff into the 210. I have a Koralin denitrator and I'll just be moving it from one tank to another.

Am I going to have a nitrogen cycle issue when I make the move, or will the live rock, denitrator, and macro-algae just continue to do their thing with no issues?

Thanks,
Rod

[houstonhobby]

Just to be clear, I am not planning to add anything during the switch (except more water). No new live rock, no new sand, no different filtration (although the filtration rate will be a bit faster).

So, the 210 will be sparsely furnished. We can worry about that as the months go by.

I have a second sulfur denitrator I could hook up if anybody thinks it is a good idea.

[thegrun]

I don't see a problem except with the sand. I would use all new dry sand since using the old sand does pose a possible new cycle risk with all the stirred up detritus. Down the road when you add more rock I would cycle it in a separate container before adding it to your new system.

[Sugar Magnolia]

Moving the rocks about will disturb some settled detritus which could spike the nitrates but it's unlikely to cause a cycle. What definitely would cause a cycle is to move the sand. I suggest using new sand and seeding it with a couple of cups of your existing sand. Make sure you have plenty of saltwater on hand to do some water changes if you see the nitrate rise drastically.

[houstonhobby]

By the way, I moved the tank over the weekend. Moved all the live rock from the 90, the sump, and the two refugiums into the dt. Don't have any live rock in the sump now ,but I do have three feet of chaeto and green bubble caulerpa. And a Korallin S 1502 denitrator. And a BRS reactor with high value GFO in it.

I moved enough sand from the old DT to give a bit of sandy bottom effect, most places it is a quarter inch or less and some places it was swept clean by the current. I think sand might be over-rated although my Amblygobius phalaena does not think so. He can't dig burrows under the rocks anymore. But he still takes the substrate in his mouth and distributes it all over everywhere. And makes a bit of his own substrate by eating the rocks themselves.

Did not see any ammonia or nitrite. Nitrates are about the same as they were in the 90 (below 10 ppm).

The inhabitants all seem happy and they love the new scape, which is a pile of rocks down the center of the tank. Does not look natural at all, especially since branching rocks and big rocks are mixed together. But it makes for LOTS of caves to swim thru.

Thanks,
Rod

[ca1ore]

FWIW I moved the contents of a 90 into a 265, including most of the old sand, and got no cycle. I did maintain the same sump, however. I think the advice to not use old sand is a wise one, though in my case the old sand had such a wealth of life in it I just couldn't bring myself to discard it. So, the old sand became the bottom layer of my new sand bed.

[DEFCLONE80]

When I moved my tank I kept the same sand and rock plus 50% of the water