# Question about Rocks



## bumbleboo (Jun 6, 2010)

I have another question! (Is it bad to start two topics at once?)

I was wondering what types of rock are safe to be with my fishies. Do I have to buy the ones supplied at fish stores? (That's what I've done so far, it's expensive!)

I mean, could I go outside and pick up a rock and put it in my tank? I'm too paranoid to do it, and I don't know the proper measures to make it safe for the tank, nor do I know enough about rocks to know whether the rock might have metal content? or something bad for the fish!

I am just wondering, maybe this is a silly question!


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## igor.kanshyn (Jan 14, 2010)

Look at this: http://www.uniquaria.com/index.php/articles/6-misc/21-aquarium-safe-rocks

If you have found a _safe _rock on a street and boiled it, it should be fine for aquarium.


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## bumbleboo (Jun 6, 2010)

igor.kanshyn said:


> Look at this: http://www.uniquaria.com/index.php/articles/6-misc/21-aquarium-safe-rocks
> 
> If you have found a _safe _rock on a street and boiled it, it should be fine for aquarium.


Thank you so much!


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## Holidays (Apr 18, 2010)

get some rocks around the river or creek, then boil it. I got some river rock from lake wilcox in richmond hill and put them in my tank.


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## bumbleboo (Jun 6, 2010)

Holidays said:


> get some rocks around the river or creek, then boil it. I got some river rock from lake wilcox in richmond hill and put them in my tank.


Okay, I'll have to go rock hunting one of these days. Thank you!


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## Joeee (Apr 3, 2010)

I was taught to NEVER boil a rock, something about opening up a gas pocket and making it explode. It doesn't sound very fun to me. I'm pretty sure there's the vinegar test to test for alkalinity and some other test to make sure it's not too acidic.


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## igor.kanshyn (Jan 14, 2010)

Joeee said:


> I was taught to NEVER boil a rock, something about opening up a gas pocket and making it explode. It doesn't sound very fun to me. I'm pretty sure there's the vinegar test to test for alkalinity and some other test to make sure it's not too acidic.


Boiling a rock kills almost everything _live_ that can be on/in the rock. It's just for that.
Vinegar test is for another purpose.


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## KhuliLoachFan (Mar 8, 2008)

If you are worried about boiling then use bleach soak for an hour, then rinse well and do a double dose of dechlorinator.

W


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## Chris S (Dec 19, 2007)

I'd suggest the bleach method as well. As mentioned, just make sure you rinse if afterwards and then let it sit in water with some dechlorinator.

The idea of using vinegar on the rock will test if it will effect your pH at all. You want to use inert rock in your tank, so if vinegar causes any fizz at all on a rock, I would not suggest you put it in your tank (unless you want to keep african cichlids or other higher pH tolerant species).


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## Joeee (Apr 3, 2010)

After going back to my chemistry notes, this is what I determined:

The ideal gas law states that temperature, pressure, and volume are all proportionate. An increase in temperature will raise volume, if there is area for it's volume to increase, the pressure increases. Eventually, this force from the pressure (I'll call pressure force) will become the same as the resistance force from the rock (I'll call this the normal force). When the pressure force > normal force, the the gas will escape and the rock will explode.

My chemistry is a bit rusty, hopefully if I'm wrong, someone will correct me.


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## bumbleboo (Jun 6, 2010)

Thank you everyone! I think I will do the bleach method and the vinegar test.


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## AquariAM (Jan 28, 2010)

Joeee said:


> I was taught to NEVER boil a rock, something about opening up a gas pocket and making it explode. It doesn't sound very fun to me. I'm pretty sure there's the vinegar test to test for alkalinity and some other test to make sure it's not too acidic.


I've boiled so many rocks of so many kinds over the last decade and no kaboom yet. When I lived with my mother I got yelled at but that's about it.

As far as the vinegar test, that's a crappshoot, you can still get a moderately basic rock, ie, granodiorite, gneiss, which will not react to the acid test due to it's composition, but will still increase pH and TDS if used in volume. The smartest thing to do is to spend an hour learning about igneous, metamorphic, and sedimentary rocks, what they're made of, what rocks are safe, etc. Learn to identify granite from granodiorite from gneiss, as they have different levels of alkalinity, and are most typically used in aquaria.


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## Joeee (Apr 3, 2010)

AquariAM said:


> I've boiled so many rocks of so many kinds over the last decade and no kaboom yet. When I lived with my mother I got yelled at but that's about it.


That's appealing to common practice, in other words it's the basic idea that the subject does action X is used as "evidence" to support the action or practice. It is a fallacy because the mere fact that most people do something does not make it correct.

It's also a hasty generalization because it draws a conclusion about a something based on a sample that is not large enough.

Cases of exploding rocks:

http://www.abc.net.au/news/stories/2005/06/06/1385064.htm
http://www.natureskills.com/stone_boiling.html


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## AquariAM (Jan 28, 2010)

I've never had a rock explode or crack... guess I learned something new 

I've boiled quartz, granite, gneiss, granodiorite, orthoquartzite. Never had an issue. Some were boiled as much as four hours. 

I'm sure it's possible. I wonder if there are other variables at work.


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## Joeee (Apr 3, 2010)

AquariAM said:


> I've never had a rock explode or crack... guess I learned something new
> 
> I've boiled quartz, granite, gneiss, granodiorite, orthoquartzite. Never had an issue. Some were boiled as much as four hours.
> 
> I'm sure it's possible. I wonder if there are other variables at work.


At least you found out before something happened. ;]


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