there is nothing wrong with bio-balls when used outside of a wet/dry application. They actually have more surface area than most (if not all LR
). Where bio-balls fall down is in the wet/dry method where the water with all the floaters fall on the bb's out of the water. That's where the stuff gets stuck. The same thing would happen with LR
used in that application.
Look and them both and think which one looks more likely to grab onto a hunk of food and not let it go,,, you round bioball or the cavernous LR
Anyway, that's my 2 cents..
Fact is if you have enough LR
in your main you don't need either in your sump.