I pulled out my my bioballs and all mechanical filtration from my wet dry filter about 3 weeks ago. Not only have I not had any problems with ammonia/nitrite but my ORP has gone from around 260 - 270mv to 380 - 390mv. Right now it's reading 393mv and is still increasing daily. I've also noticed a big reduction in algae growth. So I recommend doing it. I am using an AquaC EV120 in my sump and no other form of filtration other than lots of live rock.