Wet/Dry system in sump--Help me understand the biology!

Am I right in thinking that the wet/dry system in the sump is a biological filtration system whos job is to: oxiginate the water, create a place for bacteria to grow in medium such as bio balls or LR rubble etc in order that biological denitrification occurs thus reducing nitrates. I have seen those very porous coral balls that BRS sells for the wet/dry system over bio balls. Apparently these corral balls have mant times the surface area in which beneficial bacteria can grow thus allowing for greater dentitrification.

My current sump has as its first chamber a wet/dry system. I currently dont use it but rather house my protein skimmer there to accept the dirty water. Then I have a refugiume set up in the second chamber with LR rubble below macro algae. Then it flows to the third chamber via the baffle to the return pump. I'm thinking of reinstating my wet/dry system using coral rubble instead of bio-balls again or is this over kill if I already have loads of rock rubble in chamber 2 (refuge).

Also, why do people always claim that the wet dry system (bio balls) are a "nitrate factory". I know that it accumulates detritus but if Im using a sock that shold not be the case? In other words, when do nitrates over power the wet/dry system and actually stop the denitrification?

Thanks

 

Wet/dry systems work well, esp. when used for FOWLR set-ups. They just require a little more maintenance than do our sumps most of us use on our reef tanks. IMO, if you have a reef tank, then you likely have enough rock in the tank to take care of the biological filtration. We then save the room in our sumps for the skimmers and various reactors and such that we run.

Do you feel you need more filtration? Is that why you want to add back in the wet/dry? I would think with a skimmer and fuge you should have all the filtration you need.