I've personally used bioballs in all types of setups; FO, FOWLR, and Reef. All of which is more of a hinderance than a help later in a tank's life. At first during the initial cycle and a few months afterwards, it does help. But any point beyond that and it will start releasing excess nitrates. There are successful tanks with BioBalls and no Nitrates, but these tanks usually have many large methods of nitrate reduction including macro algae, deep sand beds, lots of live rock, and many water changes. But, that's just because the nitrates are undetectable. The BioFilters (BioBalls, BioWheels, etc) still release nitrates, but the other forms of nitrate removal take it up as fast as it's released. It's really a delicate balance. Anything that would add too much nutrients would send the tank into a nitrate rich environment. Heavy bioload, adding large messy fish, letting a dead animal decompose, or even accidently spilling food could cause it to become imbalanced. Usually, if you are using a BioFilter filtration method, and your tank cannot cope with all the extra nutrients, you will have a tank full of algae.