Useful to understand that rock is not 'just rock.'

[Sk8r]

A. Bacteria may live inside it: https://en.wikipedia.org/wiki/Endolith
B. Rock is generally not quite that dry inside. http://www.sciencedaily.com/releases/2014/06/140612142309.htm

and C:limestone rock, that spends its days in the ocean, has a lot more going on in its pores and crevices than just a thin skin you rapidly apply to the surface.

So when you're prepping your rock for your tank, don't think of its conditioning as only a 'skin' you slap on, but something with a bit more depth to it. It may have a phosphate content that will move verrrryyyy slowly to the tank water over months. It has bacteria in the nooks and crannies that you can see, and some that might not be that apparent to the naked eye. A lot goes on at the surface, yes, but just as one human lung, if truly all its passages were flattened out, would cover a football field, so really good rock for your tank is kind of lacy and full of crevices---limestone, old coral, that sort of thing, which is porous and affords a lot extra bennie of processing for your tank.

 

[CarrieB]

How long can I leave a rock out of water before significantly impacting the inhabitants?

I'm acquiring an existing tank and worrying about the process of arranging the rock with damaging it. Should I have water in the tank while I construct?

 

[Sk8r]

Quite a while, if not overheated or baked in the sun.
When I set up my 54 reef, I received rock which had been taken from the store, wrapped in thick wet newspaper, put in a garbage bag in a pasteboard box, tossed in the back of a pickup along with 54 gallons of water and bags of sand, and driven, in a fierce snowstorm, to my place, set out on the living room floor during setup, and finally put into the tank, in icecold water. As the water warmed over the next week, all sorts of creatures, including live coral and aiptasia began to unfold. And I counted some 50-odd species of marine life that survived on the rock and survived a fullblown cycle, all but two of them really wonderful. Cold isn't necessarily a detriment in a situation like that: it slows down chemical processes, including decay and drying out.

 

[CarrieB]

Thanks so much for the reassurance! Rock is now in tubs in water from the tank, riding in the trailer in 39 degree weather. No snow. Sounds like we should be good.

 

[Tarawa]

I'm cycling some marco dryrock to replace the current rock, which started out as dry when I set it up. Do I have to worry about the rocks absorbing nitrates at all?

 

[Sk8r]

The water came in as new ro/di saltwater, right? Warm saltwater will dissolve stuff out of the rock, notably phosphate: saltwater is real good at dissolving minerals. Nitrate, however, comes most often from biological processes, ie, the waste of living things, and our water changes generally carry that away. Nitrogen is part of what we breathe in and eat, and it goes into waste. I'm not a chemist or biochemist, understand, but I don't think so.

 

[Tarawa]

yeah, its fresh RO/DI saltwater in a garbage can, and I added some ammonia to about 2ppm and threw int a sponge that was in the sump. Powerhead and a bubbler for more flow. Tho I dont think it was as seeded as I hoped. Three weeks in and still ammonia, which is fine, I'm in no hurry to swap out the rocks. =D