lava rock

[scottp]

can I use lava rock instead of bioballs doing FO using a 55 for a sump half of the tank using for bioballs but I still need about 500 well with xmas coming can I put lava rock on top of the bioballs in there now and be ok

[Sk8r]

Volcanic rock may contain metals. Not totally sure of that, but I'd be suspicious. Try rock rubble incl. old corals, etc.

[1010]

I was curious about lava rock i have some in my 29g I dont think they have effected any thing. it has been in there for a year with a few leather some coral line has started to grow on it.

[sndwave80]

There are curtain types of lava rock that are only for aquarium use due to the metals/ minerals in the area they are excavated from. I would link you'd be ok as long as they are advertised safe for fish. I know the lava rock sold as stores like Menards are not safe to use, so I have been told by the sales staff there. That rock comes from all over and there is no guarantee what is in it.