They were a Godsend at one time. They house the bacteria that convert the very dangerous Ammonia into Nitrites and also the bacteria that turn the Nitrites into Nitrates.
Then came along live rock which has plenty of surface area to house your bacteria, gave you some place to put your corals, and also provided a natural environment for your fish to live in. That's when people started removing their bioballs.
Because of their nature, they cannot house denitrifying bacteria like live rock can. This has lead many people to call them Nitrate Factories which is a little unfair. Most people with bioballs and very high nitrates usually have tons of detritus sitting in with the bioballs and rotting. These same people can remove their bioballs and get no improvement on their Nitrates unless they also remove the detritus. _________ Curt  |