bio balls

[shimmer]

quick question...do bio balls in a sump work if sized properly and with a skimmer etc. Just curious.

 

[lcstorc]

Depends on your description of work. They work fine for a FO or A FOWLR but not so great for a reef. They are good at converting amonia to nitrite and nitrite to nitrate but they cannot convert the nitrate to a harmless gas like the LR can so you are left with nitrates in the system. LR has the extra type of bacteria to complete the cycle.
Another problem with them is that they tend to trap a lot of detrius.

 

[Gina]

Bio balls are a nitrate factory. You can use them if you want but, most everyone I know doesn't bother with them.