I would have to say keeping my water parameters stable. I would test for my ALK using 3 different test kits day and night. I still test for my ALK levels every morning just in case my Ca rx failed.
I also keep my PH levels above 8 at all times. I dose Kalk at night using LM3 via kalk reactor.
Lastly, I feed my tank really really heavy while doing water changes every other day in small amounts. I feed oyster eggs, phyto feast, roti feast, cyclopeeze to my LPS, and Pappone once a week.