• Looking to buy a cephalopod? Check out Tomh's Cephs Forum, and this post in particular shares important info about our policies as it relates to responsible ceph-keeping.

Lava Rock Bad?

Jun 3, 2007
One of my fellow reefers told me that I shouldn't have just lava rock in my saltwater setup - especially because it was sitting in freshwater for a long time.

There is no growth on any of the lava rock, so I decided to put some Fiji and tonga live rock in there. I bought about 35 pounds of LR today and dropped it in my 50 gallon.

I guess my question is should I leave the lava rock in there or slowly take it out over time?
I used a lot of lava rock as base rock. It is very porous, so if you mixed it with live rock, it should become "live" after a few months of being in with the real live rock. The only problems you should have from it being in a freshwater tank are if you used any tank treatment chemicals.

The problem with using it is that it's not serving as a biological filter like real live rock. You should use it primarily to fill space, building on top of it with the live rock.

I found that lace rock is closer in appearance to live rock than your typical lava rock, but hey, as long as it's porous it will eventually serve better purpose than a lot of the stuff I see used as base rock.

We actually have a 30lb chunk of limestone or "holey" rock in our seahorse tank that was ugly green when we started the tank, but now it's covered in coralline, worms, and corals.
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