DIY live rock

[sammydee]

Hi. Anybody who has made live rock out of "oystercrete" I would be grateful if you could help me.

My first two mixes were way to wet and crumbly. My third and fourth were porgressively less wet and my fourth was almost completely solid, however it was not porous in the slightest.

My latest mix was much drier (soggy oatmeal consistency) yet this has gone the other way and is extremely crumbly after two days curing?

Maybe it was because it got very cold and froze, or maybe it was too dry, or too wet, or what. Please help me I'm confused

 

[Navarre]

if you add rocksalt to the mix then it will slowly dissolve and form the cavities and porous texture you ned. the same can be done with pasta but its gets a bit messy

 

[sammydee]

Well I think the original mixtures were too wet to be properly porous anyway. A dry mixture creates air gaps which makes it more porous. I think because we had a frost, the rock froze and this weakened it considerably. I will break it up and make it into another mixture and try again.

BTW my proportions were:

2 cups cement
6 cups oyster shell
2 cups silica sand

 

[Navarre]

I definately would not use silica sand.
Aragonite is the usual sand used to create liverock.

 

[sammydee]

You don't think? On a lot of the sites I researched, and on reef central people said it would be fine to mix ordinary silica sand in with the oyster shell.

I'm going to make some more of the same consistency and see how strong it is.

 

[Navarre]

the reason i would not use silica is because "some" silica sand can leech silicates into the water and thus cause massive algae blooms. Whilst perhaps the oystershell will help stabalise water and PH, there si no sustitute for aragonite that will not leech silicates and be a far better foundation for water buffering

 

[sammydee]

Well some people swear that rock salt makes their rocks really weak, whereas you have used it with no problems...

The only way I'll find out is if I try it I think, as everyone has different opinions.