Is lava rock reef-safe?

[Bear22]

Does an emoji count as a graphical means of commenting? If so, I guess the statement "I have no more comments here" can be thought of as a vacuous statement.

 

[fish_collector]

I would not put lava rock in my tank. Too much chance of heavy metal release from it.

I feel this was an adequate response to the OPs question of whether or not lava rock was reef safe. Randy offered his opinion and based it on his risk tolerance, in this case he chooses not to use lava rock in his tank because of the chance of heavy metal release. There were no absolutes, no claims. Not really necessary to say it any differently.