<a href=showthread.php?s=&postid=11577124#post11577124 target=_blank>Originally posted</a> by Brenda74
Why is the live rock better?
I am trying to gather information as I would like to start a tank. Thanks!
The bacteria on bio-balls, due to the efficiency gained by increased O2, outcompete the live-rock for ammonia and nitrite.
This starves the nitrifying bacteria on the LR and all of the nitrification occurs on the bio-balls.
Additionally, for effecient de-nitrification, the nitrification, must occur in close proximity to the denitrifying bacteria. The de-nitrifying bacteria is deep in the pores of the LR, but not anywhere near the bio-balls. So the nitrification is now occuring far from the denitrification. The denitrifying bacteria, then dies off some and it's effectivness is limited. The end result, is that more nitrification is occuring than denitrification and the nitrate levels rise.
The second issue, is that the bio-balls collect detritus and other junk, and because they are not accessibsle to fish, snails etc, the junk is not consumed. The result is that this stuff decays and realeases further nitrate and other nutrients directly into the water column.
IMO howver, replacing bio-balls with LR is not very effective. This is because the small peices of LR are unlikly deep enought to host a lot on denitrifying bacteria. I would perfer to replace them with cheato, or just get rid of them altogether.