I run an SPS tank, I've been reasonably successful over the years. I schedule a 20g water change every two weeks. This means every 10 weeks I need to spend $50 on salt. That is a requisite cost of the hobby. My corals grow at stupidly fast rates, my longest lived fish was 9 years old, and everything does well in my tank. I don't supplement magnesium, I don't use zeovit, I add nothing that doesn't come from my Ca reactor or the water change.
As it's pointed out, the water change is at the very least some "fresh air" for the inhabitants. I cannot understand for the life of me why anyone would not want to do water changes. Is the 30 minutes twice a month too much time invested? $200/year in salt too much money? Or we think that fish prefer to swim in their own waste over fresh water? I don't get it. Kinda like not washing your underwear between wearings, IMO
