curing cement rocks?

[rc]

i have seen many different directions on how to cure cement made rock, they all seem to be geared towards someone already having a tank up and running and wanting to add cement rocks, what if you are setting up a new tank, could you cure the rock in there while the tank cycles (kill 2 birds with one stone)??

 

[Octopus_Reef]

I don't see why not, Check www.garf.com they make and sell alot of them, But if you are cycling a tank for 3 months for an octo and cement rock only takes 6 to 8 weeks to cure I don;t see what it could hurt ...............

 

[rc]

im not sure how the ph swing would affect the bacteria growth (or the release of kw in large amounts) the cement rock is actually going to be for a reef tank, im upgrading from a 46 to a 92g corner tank, my octo tank has been ready for about a month now but i have become so fascinated by the millions of little critters in there that im letting their numbers grow before i introduce a baby octo

 

[rc]

what does anyone think about adding a protein skimmer or filter to the curing tank, might this speed up the process?

 

[mikeconstable]

Curing Concrete

It is the soluble calcium hydroxide which causes the high pH, so if this can be stabilised the concrete is 'cured'.
Contact with carbon dioxide (in air or water) insolubilises the calcium on the outside as carbonate, just takes time, and seals any strong alkali in the centre of the 'rock' where it cannot affect the aquarium if the rock is not broken.
Sodium silicate (waterglass) solution used to be used to cure concrete pools, making insoluble calcium silicates to help seal the surface (instead of carbonate), but the caustic soda produced in solution still had to be washed away.
Both the above techniques add to the surface. Attempts to neutralise the alkali using acids tends to strip the surface off the 'rock', exposing the aggregate which reduces the surface area of cement able to supply alkali.