Sandstone decor, and Vinegar test?

[darylann]

I picked up a couple of sandstone rocks for my daughter's tank. They look cool and the fish like them, but I'm wondering if they will affect the PH at all? And what about collecting rocks for her tank from streams or lakes? Should they be boiled? What's the vinegar test about that I've heard mention of?
Still learning ... and appreciating any help!!!

 

[Blinky]

I've got 'picture rock' in one of my tanks, which is layered, multi-coloured sandstone - it doesn't affect the pH at all. I'm not sure all sandstone is the same, but the vinegar test should tell you if yours is okay to use.
Just place a few drops of vinegar onto the dry rock, and see if it fizzes at all. If it does, you know the rock contains substances that will dissolve in the water and cause the hardness and, therefore, pH to rise. It's also important that there aren't traces of metals in the rock - some rocks have lines of various metals running through them and aren't suitable for aquaria.
Once you determine if rocks are okay to use, just boil them for a few minutes (to sterilize them), let them cool off, and they should be fine.