ARE THESE ROCKS OK FOR AQUARIUMS?

[DPHAN86]

I'VE READ THAT SOME ROCKS CAN RELEASE DIFFERENT CHEMICALS SO I'M WONDERING IF THE ROCKS THAT I HAVE ARE OK FOR MY TANK.

http://www.youtube.com/watch?v=-kXEILgyguE

 

[aclockworkorange]

Here are some ways you can test your rocks: http://www.ehow.com/i/#article_5838701

 

[Moloch]

Step 2 & step 4 both test for calcium...I don't even know what muriatic acid is, much less where to find it. Is this the same test? If you do the PH test over a few weeks in water do you not need to use the muriatic acid?

Good link though, I'd been kind of curious about this. Haven't yet gone looking for rocks to use, but knowing how to test them, I might keep my eyes open for them now