# how to check if stones are safe for the tank.



## jc0522 (Oct 22, 2009)

so i found some really nice looking rocks on the side of the road today. i read somewhere (i forgot where) that there is a way to test if its safe to use in a freshwater tank. anyone know what to do!?


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## davemonkey (Mar 29, 2008)

If vinegar makes it fizz, toss it.


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## husonfirst (Sep 27, 2009)

You will also need to see if the rock changes your water parameters (ph, gh, etc.) at all.


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## Philosophos (Mar 1, 2009)

The vinegar/HCL/H2O2 test is a very good start. I use it for any early test on a rock.

Look for differences between the weathered outside and inside fractures; if things that looked silver or yellow suddenly look green, red or orange then you've got a stone leeching iron or copper most times. I don't make a big deal over a little iron my self, but copper is obviously one to skip out on.

-Philosopos


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## mudboots (Jun 24, 2009)

Vinegar and Peroxide are certainly going to be the easiest household items, but JUST IN CASE (plus I'm in a good mood this afternoon and can't resist posting something in every thread I see) your kids used up all the peroxide and your honey-bunny drank the vinegar for whatever reason you can also use Muriatic acid.

D'oh! Looks like Philosophos already included HCL (Muriatic is basically, or chemically rather, I N HCL). Oh well, good luck and welcome to APC!


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## geeks_15 (Dec 9, 2006)

This is kind of difficult to explain and subjective, but I scratch the rock with my fingernail. If the rock is easy to scratch and make a mark on the rock it is probably a softer rock and therefore more likely to dissolve (very, very slowly - it won't disappear) in your tank and change the water chemistry. A rock that is harder to scratch is more likely to not dissolve in your tank, and therefore aquarium safe.

If you compare the scratch test with the acid/vinegar test you can get an idea of what I mean and get some practice comparing good aquarium rocks and bad ones with both tests. That way, after you have a little experience, if you find some cool rocks and don't have any vinegar on you, you can make a guess with your scratch test.


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