Is this good rubble?

I found this on ebay and was wondering if anybody has ever purchased something like this before. I was going to swap out the bioballs in my tank for rubble and came across this stuff. Do you guys think this will work?

 

Sorry, forgot to attach the link. Here it is:

2 LBS. LIVE LAVA RUBBLE ROCK - BIOFILTER, REFUGIUM - eBay (item 260430341478 end time Oct-14-09 21:32:47 PDT)

 

i could be totally wrong here , but i would think the rubble would end up being like bioballs in the sense it would also trap all the detritus too.

 

I'd keep the bio-ball, they have a bad unfounded rep. As long as water trickles over them and they are not submersed all works well.....very well.

 

The LFS where I work currently uses lava rock in their filters. I don't particularly see any faults with it. Personally I have never used it in my tanks at home, but I do remember someone, somewhere saying that lava rocks may contain heavy metals which are bad for saltwater aquariums.

 

I know several members have purchased live sand from the same seller but I don't remember seeing anyone that tried the rubble.
I am curious about this as well, I was considerring adding some to my sump to help encourage a pod population.

 

Ok, I think I'll just stick with them. The water trickles over them just fine and I haven't had any problems with nitrates. All of my tests come back 0.

Good thing to know about the heavy metals. Thanks for the heads up.