I do a 5gal water change wkly (didn't get to it this week
) But even with the eco-system style sump I do run a smallish skimmer. So mid week I add a few drops of Coral-Vite, Strontium & Molybdenum, Iodine & Reef buffer as needed. DT's EOD. I continually top off w/a weak mix of kalk. I shut the lights down on my refg 2 hrs nightly to allow the pods to come out to feed.