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I went out side and saw some slate. So now i have slate. After breaking it up a bit i got this going.



I have some fish who would really love this cave. I boiled the rocks for about 30 mins. the top piece was too big to fit in the pot so it is not boiled. i was thinking of cleaning it with hydrogen peroxide. what else should u be doing to the rocks before i put them in the tank. The tank is newly cycled. 5 weeks old. Has fish in there now including a brand new baby L144 Blue Eyed Yellow Bristlenose Plecos from Debbi. I want a housing for the pleco and upside catfish until i get a piece of driftwood in there.

should i just let the rocks sit in a bucket full of water for awhile?
 

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Does'nt look like slate to me either. Have you done the viniger test to see if it is aquarium safe?
 

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Slate breaks off in small, skinny chunks, not large thick ones.
 

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Correcting typosRun it by the Geology Dept. at Cal Poly Pomona, they can verify whether it is slate, but I d not remember any in that area (I used to work at Cal Poly). Could be shale, which is unmetamorphosed slate and not as safe. Just call and ask when would be a good time to drop by, most profs I know are very happy to spend a few minutes helping.

Besides the vinegar test, try the lighter test - if a cigarette lighter flame applied to the rock produces a burnt smell, the rock has organics in it. Remember, that is petroleum country!

If you are unable to take it to Cal Poly. mail me a chip and I will examine it - I'm a geologist (retired).
 

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please make sure you consider this!

I just wanted to mention that the vinegar test, which involes driping white vinegar (acidic) on the rock in question. If there is a fizz, indicating a reaction you can make the generalization that the rock contains calcium carbonate/limestone (alkali) which can raise the general and carbonate hardness of the tank water. This is generally not benifitial for the planted aquarium. I would not make the assumption that the vinegar test determines if the rock is "safe" for the tank. I think that everyone can agree that collecting your own rocks has the potential to create problem in a tank, if you are not a geologist. That said I have used slate and shale in my own tanks. Shale is more risky because of organics :)proud:mosasaur). I have tanks which i used oil shale(maybe), which can be split into paper thin peices by hand, but mine doesnt look like what you found. I have read that this shale is very risky because of the organics, but I have never had problems with it other than it will crumble over the long haul. I am not saying that it is safe, only that you must determine if it is worth the gamble for yourself.
 

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That said I have used slate and shale in my own tanks
In both cases, there is some chance of disseminated pyrite, in particles too small to discern easily This is especially true with shale that has some organics, but I have seen pyrite in slate also. If you have a 10 power hand lens, use it - if you cannot see pyrite with it, you are almost certainly safe!

All in all, the safest rocks are granite and a clean, pale colored sandstone. But they are also a bit boring! The dark "granites" called diorite and gabbro are safe and more interesting. Basalt is the fine grained equivalent of gabbro; obsidian and rhyolite are the fine-grained equivalent of granite, and these occur in the Agoura area. In fact, I have collected obsidian myself near Moorpark, but I would not use it in a tank - way too sharp!
 
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