any rock experts? are these safe?

[adixon816]

Rocks to stay away from in aquaria are limestone and alabaster as they will "melt" releasing toxins into he water. Urs look a o.k. to use. Granites,river rocks, slate and most landscaping type rocks are all good to use.

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I'm not so sure about limestone people use it to buffer pH in African tanks. Any evidence of this because I'm curious.

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