Filter Media stumble

[da1jewfish]

I stumbled upon about 15lbs of cinder lava rock on ebay for cheap fresh from Hawaii. It looks like lava rock only black, they are all small pieces 1/2" or less. I use regular lava rock in my fresh and saltwater tanks, can I use this? Any help will be appreciated.

 

[ceatwood]

I've only heard of it used in wet/dry filters

 

[tanker]

Too sharp for FW fish IMO.

 

[da1jewfish]

actually thats what I was refering to... in the filter itself, whether it be in a power filter or wet/dry, but in a filter. Is it safe? will it leach anything? It is very pourous and should be good for bacteria growth. Thanks in advance