Cement and Ph

[Sampson]

I am considering creating arogocrete rock forms for a salt water tank.
Useing plans from the garf .org site, however it is hard if not impossible to get the recomended cement.
I live on an island and it is not imported.
Locally we have the common portland cement.
What I need to know is if I create the forms and place them in the ocean- how long might I need to leave them before they have a safer Ph.?

I am unable to use proper natural live rock as there are local restrictions and licences that need to be taken into account when it comes to corals.
The forms are for a public display not home use.
So this may just be easier to do.
Thanks

 

[Nic]

you can use type 1 portland instead of type 3 and since your gonna cycle it in the ocean I would leave it for a month....

 

[Sampson]

thank you

 

[Nic]

just keep it in mind the longer you leave it the better it will be more bugs bacteria and coralline algea will grow on it

 

[Sampson]

thanks for your suggestions
pretty much as I thought, its feels better to double check.
As I originally stated -the forms are intended for use in a public display,
Since posting my original question, I have come up with a solution that seems acceptable to the fisheries dept, (they do not allow the collection of any corals from the wild) They will allow the arogocrete forms with some encrusting lifeforms and I will have to use artifical corals build up the rest of the reef display.
Hope to (one day) post some pics on the MFK site

 

[Nic]

so if you left it out there for a year and they became encrusted with a lot of different corals etc... they wouldn't let you collect them????

 

[Sampson]

What they are hesitating about is -they do not wish to even appear to bend the regulations forbiding the collecting + keeping any corals and inverts, they have recently have arrested people or sent warning letters to persons engaging in shell collecting and collecting for the aquarium trade. So a public aquarium utilizing a large percent of " collected " corals is not politicaly correct at present.
They will come around slowly.