I've been doing reef tanks for about 2 years now without any skimmers. I've always used either a fluval 404 or Filstar cannister filter. My brothers don't use skimmers either (one should) and everything seems to be ok. I'm currently running skimmerless on both my 54g corner and 10g. I just clean the media evertime I do a water change. I rinse them out using the water that I took out of the tank. Once your tank matures, you'll see pods growing in the media, that's why you don't want to rinse the media with fresh water. I also have some halimeda plants in my tank that help combat the bad algae. Just control your feeding, do frequent water changes, have a good clean-up crew and keep your livestock at a minimal and everything should be fine.