How to determine is 'wild caught' rock is safe for aquarium

[Angry the Clown]

Hi All,

Here in central Texas, there is an abundance of cool rocks that I would like to clean and use in my aquarium. How can I determine what is safe and what isn't? Is there an easy way to figure it out?

TIA!

AtC

 

[Purrbox]

The best way would be to fill a bucket with water. Run the full gambit of tests on the water and record them. Through your rocks in the bucket and let them soak. Test again periodically and compare your results the the original results. If after at least two weeks of testing you don't see a change in the water chemistry, you're probably safe to add them to your tank after a thorough cleaning. You can always test for longer to be extra safe.

There are some other quicker methods that involve using some acid to check the composition of the rock. The problem with these is that they aren't always accurate if the acid is too weak, or the rock is made of several things and the part you tested was fine but another was not.