I will say this I ran skimmerless for many years with never any problems , at that time I was even running DSB's I just made sure I did a weekly water change and I kept an awesome sand crew in my tank, I stayed away from pod eaters and bristle worm eaters too, kept lots of spagette worms, mini brittlestars, peanutworms, nass snails, any detritus eating critters. and tried to stay away from putting anything that hunted these critters for food.
and my skimmless tanks always did great.
But I will say this once I dropped using DSB's and went to using skimmers my tanks are a lot more forgiving.
with my skimmer pulling DOC out of my water column and my DSB not having to worry about keeping up with a good crew. life is a lot easier on me...LOL.
PS. and if anyone is looking for a good smaller tank sump skimmer I still have my Like new Urchin skimmer and mag 3 pump for sale.
Jim