The Planted Tank Forum banner
1 - 1 of 7 Posts

· Registered
2,315 Posts
It's kinda difficult using names like that, since they aren't really official, and I've seen different types of rocks labeled with the same name.

Aside from that, granite, lava, and petrified wood are generally inert.

I believe Texas holey rock is limestone based, but I'm not certain. I think most lace rock is as well, but I've also seen a type of weathered igneous (andesite maybe? I can't remember) also called lace rock.

So, limestone will generally raise your hardness and pH. Most holey rock and lace rock will probably be limestone based, and also raise pH and hardness.

Igneous rocks (granite, basalt, lava rock, pumice, obsidian, etc.) are almost always inert/safe.

Metamorphic rocks are usually safe (slate, gneiss, schist, quartzite, etc.)

Sedimentary are more difficult, some sandstones and such are fine, but a lot have carbonates in them, which will affect pH/hardness.

Also avoid rocks with metallic-looking particles, or irridescent type effects - A lot of times these are related to compounds containing heavy metals, which while not directly affecting pH or hardness, can leach toxic compounds into the water.
1 - 1 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.