Amphiprion
Premium Member
I have seen very nice skimmerless systems. The tanks themselves may not have been pristine, but the corals didn't seem to notice the difference. All had good coloration and excellent health. My tank actually recently (funny story) ran without a protein skimmer for a couple of months. While it may not be enough time to establish the biodiversity a full time skimmerless system, I did notice the abundance of other organisms and no change in the corals.