There are many people that
DON'T use skimmers and keep very successful reef tanks. There are other methods for exporting nutrients like frequent large water changes, a DSB and vegetable filters. I prefer a skimmer, to me it's just alot easier and it's so effective why wouldn't you want to use one ? I know it does remove important elements and plaknton but I've got plenty of food in my tank !
I don't recommend beginners going skimmerless but if you have plenty of experience and keep a low bio-load it can be accomplished JMHO
