Originally Posted by
AquaKnight
http:///forum/post/2723526
That said, I have before used pieces of granite I collected in NC/Tenn. for some freshwater tanks, without issues. Perhaps the more corrosive nature of saltwater might cause more, however.
most likley the amount of granite you used and the rate of arsenic dissolution into the water column was mitigated by your water changes. it can take a long time for something to die from slow arsenic poisoning.
A few years ago a friend of mine set up an african cichlid tank and used nothing but granite, granite rubble for the bottom, granite stones for the decor, and he couldnt keep fish alive for more than a week, it turned out in the long run after many weeks of researching and testing that the arsenic amounts in his water was killing off all of his bacteria so every fish initiated an ammonia spike. can you imagine one fish ammonia spiking itself to death in a 90g? you could set up a brand new tank and not have that problem, We do not know if the arsenic was high enough to kill the fish but it did kill the bacteria water samples taken to the university showed only dead bacteria. arsenic levels were astronomical (probably due to the granite rubble as the large surface area and dust content would make a high surface area for arsenic dissolution.