# Using GE II 100% Silicone to Glue Rock formations.



## Roberto B (Dec 3, 2014)

I used the subject product to glue decorations and rock hiding places for my Cichlid tank. Not yet put in aquarium and has cured for 48 hours. Is this stuff toxic at all. It is the window/door/attic/trim/flashing type.


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## Kanorin (Apr 8, 2008)

See this thread, which is stickied. I think it may answer your question. Someone comments about Silicone II half way down the first page, but I'm not sure if it is the EXACT kind that you have.

Does yours say if it contains any fungicides?


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## Mcdaphnia (Dec 16, 2003)

Two issues. The one you asked about is that curing silicone is toxic. The acetic acid fumes of Silicone I can harm humans as well as pets in or out of the aquarium. After curing, most silicones are non toxic with the exception of bathroom and other types that contain a mildewcide. Silicone II like your product, produces ammonia for a while, which is very toxic to fish. it also has a lower adhesion strength so the rocks are even more likely to separate from the silicone.

The second issue is that silicone is not suitable for all rocks. Silicone does not stick well to slate and other rocks with an oily feel. I glue rocks together with waterfall foam. It is dark, almost black and so does not stand out like any exposed silicone. It adheres to all kinds of rock I have used it with, and because it is designed for ponds it is nontoxic and UV resistant. It does not yellow and get brittle like silicone can.


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## Roberto B (Dec 3, 2014)

Sorry for the late thank. It was slate I was using and it fell apart before placing in tank. Project abandoned. LOL


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## Mcdaphnia (Dec 16, 2003)

Shale will fall apart in water but slate should not. Hoever slate is one of the rocks silicone will not stick to permanently.


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