what type of filtration sustem are you using ... HOB, Canister, Wet/Dry?
There is always different opinions on Bio-Balls, some will say good, some will say bad. I don't have an opinion on them as I've never had to use them. I went to my LFS and asked if they had any LR rubble I could have, sure enough there was a whole pile of it in the corner they needed to get rid of before a new shipment came in!