Sounds like a bio pellet reactor. They sell them on bulk reef supply. I've heard rumor they can cause your params to get out if wack. I have never used one though.
I met a guy recently that had not done a water change in 5 years. He didn't use any reactors and rarely added calc for his corals. He didnt even test. He claimed he didn't even feed his fish but they looked healthy. He said they ate pods
So I guess it is possible but I wouldn't recommend skipping water changes.