stones from houses

[blavis]

can the stones that are put on the side of houses be used in tanks? im talking about the decorative stone like in the following link;

http://www.centurionstone.com/

I have access to a lot of it for free and was curious.

thanks.

 

[boldtogether]

It is a foamed portland cement and it would probably leach dyes and other negatives into the water. Foamed cement is basically aerated portland cement. The air that is introduced into the mix before forming creates spaces(bubbles) inside the mixture. As it curers, the bubbles stay and this is what makes it so light weight.
Anyway, it would be cool but I wouldn't use it.

 

[blavis]

thank you sir ( or ma'am)

 

[Masterfulgaze]

Foamed cement is basically aerated portland cement.

Saltwater guys have been creating DIY Live Rock for ages and the main ingredient is portland cement. If that's what this stone is made of then it shouldn't be a problem. The problem is that cement leaches things into the water so it must be cured in water for several months before it is safe to put into an aquarium.

Here's a good link on Reef Central about DIY Rock that you can look at.

http://www.reefcentral.com/forums/showthread.php?t=1286738

 

[deluther]

Saltwater isn't freshwater and cement makes it difficult to keep a low pH. I would seal the "stones" unless you have a high pH tank (like the saltwater folks). If unsealed I would worry about dyes from the manufactured rock. You could always email the company and ask how the cement is colored and if any toxins are used in manufacture. Another option, put one rock in a small established aquarium with a few fish that you won't mind losing and wait a few weeks or months to see if they die.

 

[CHOMPERS]

The "stuff" in question is calcium carbonate, calcium oxide, and calcium hydroxide. All of which will obey the law of diffusion and move from the area of high concentration (the rock) to the area of low concentration ( the tank water). All of the chemicals will increase the pH to around 8.4 to 8.6. Calcium hydroxide at its worst can be up to 12.3 (your tank won't get that high).

The bottom line is that artificial rock isn't suitable for freshwater. And it isn't suitable for most saltwater tanks either since it also releases large amounts of silicates too. The proper rock for either FW or SW is very inexpensive, especially when considering the long term investment.