Originally Posted by fishieness
lava rock, lime rock, any of the type of rocks at your LFS that they sell as base rock will eventualy become live. I wouldnt go diggint up stuff form your backyard though because you never know what it is made out of and what it could releas in yoru tank. The advantage of live rock is it is very very porus, making it have a much greater surface area to grow colonizing bacteria to break down waste..... This is why i dont buy huge 10 pound pieces of live rock. Because 3 10/3 pound pieces would have more surface area. it is the same thing with live rock compared to base rock. However, there is a site that sells basicaly dead rock. But it is live rock just with nothing living on it. It is sold for only a dollar a pound w/o shipping, will become live, and obviously doesnt needed to be cured. Im contemplating getting some. Of course for the first while it will be plain white, but in a mature tank will eventualy get some color.
I read somewhere that lava rocks shouldn't be used in saltwater. I just buy lace rocks to use as base rock, make sure you move the sand off the bottom and place the rock against the glass bottom then move the sand back into place. Do have a QT tank available to put your inhabitants into if you have any inhabitants cause you'll have a huge sand storm. Make sure you scrub and wash the lace rocks clean before placing them into your tank. Then you can buy cured live rock a few lbs at a time to add to your tank when you have the budget. Good Luck! :happyfish