rotate. and make sure your blackworms are FRESH and cleaned well. remove white ones and never let cloudy water sit.
THERE IS A RISK of parasites with live blackworms. I had one take out a stingray once. -devastated-
HEAT. during sandy this happened to me and i in increments poored boiling water in to the tank. PLEASE make sure no fish are in the immediate vicinity where the water is going. it will immediately dilute and become non boiling dont worry but it does help keep temperature high