Replacing bio balls with live rock

[GatorDrew]

My tank has been setup for about 1.5 months. I would like to know the process of replacing my bio balls with live rock. I heard that just changing them out all at once can lead to an initial "system shock" in that nitrates (or nitrites?). What's your opinion?

 

[KahluaZzZ]

First you gotta know a little bit about the nitrogen cycle. Right now you bio-balls are great to harbor a specimen of bacterias that convert ammonia (NH3) to nitrite (NO2). Those 2 are more toxic than what you finally get with bio-balls : nitrate (No3). The bio-balls are often used when people have only fishies, and hardy ones. The inverts can't handle much nitrates on the long run. Good quality and amount of live rock can do the job for ammonia, nitrite and nitrate since it harbors all those great bacterias. The system shock you mentioned can be easier if you place the live rock when the bio-balls are still there. Then, let's say you got 50 bio-balls in there...pull one or 2 out every day and the translation will be easier. If you got no livestock in your tank you could just remove the bio-balls. Be prepared to have some little parameter swings when you add the rocks because there can be some die-off ( decaying organics ) even if the rock is supposed to be cured.
I suggest you read a little on this site : www.wetwebmedia.com