# testing rock for aquarium use



## jrdeitner (Feb 7, 2010)

Before it was my understanding that, when doing a vinegar test, if the rock fizzes it's
A
Good
Thing and the rock is safe to use. I was reading
Some
Sites and they said the complete opposite. Maybe it was geared towards freshwater though. Please set me straight on this! What common rocks are safe to use? Thanks in advance.


----------



## bmlbytes (Aug 1, 2009)

A rock that fizzes is going to make your water more alkaline and have a higher pH.


----------



## TheOldSalt (Jan 28, 2005)

Which can be either good or bad, depending on what you want, so it's hard to say overall if it's bad or good.

Stay away from basalt, cement, asphalt, limestone, talc, and sandstone as a general rule, but most other rocks are okay.


----------



## jrdeitner (Feb 7, 2010)

the LFS is selling lava rock, i thought lava rock is poisonous, so i asked them if it was real lava rock or synthetic or just sold as lava rock. they said it was real lava rock, is this stuff ok to use?


----------



## TheOldSalt (Jan 28, 2005)

Usually, yes, it's fine, as weird as that sounds. You should soak it for a long time first to be safe, and of course it will want to float, which can be annoying.


----------



## Guest (Mar 6, 2010)

i have 2 lava rocks in my 55 along with some other rocks. they are perfectly fine for use in the tank.


----------



## ron v (Feb 24, 2005)

TheOldSalt said:


> Stay away from basalt, cement, asphalt, limestone, talc, and sandstone as a general rule, but most other rocks are okay.


I thought limestone is OK for high PH tanks... No? I have some I was about to use... And it's not cement. The word is concrete. Cement is a powder! Nitpicking... I know. Sorry Salt.


----------



## bmlbytes (Aug 1, 2009)

Well it wouldnt be good to add cement to your tank either.


----------



## Cacatuoides (Feb 2, 2009)

lol, that might have an interesting effect...


----------



## jrdeitner (Feb 7, 2010)

Cacatuoides said:


> lol, that might have an interesting effect...


 haha maybe but im trying it on my tank!!


ok great i really like the look of lava rock. thanks everyone for your answers


----------



## emc7 (Jul 23, 2005)

Ron, limestone will really up your pH/hardness. But if you are keeping African cichlids, its actually great. I use sandstone as well. I don't like lava rock because its sharp and my aggressive fish get scarfed up during chases.


----------



## jrdeitner (Feb 7, 2010)

i dont plan on keeping aggressive fish, but do you think it would help if i sanded the sharp edges?


----------

