Thermally-conductive laboratory bath media can be used to replace conventional wet media or dry solid blocks in existing thermal baths for heating or cooling samples with advantageous maintenance and microbial control benefits. The media is typically in the form of metallic or metallic-coated pellets that have rounded edges, hardened surface, a smooth polished finish, and are sized small for efficient thermal communication between pellets and samples. Laboratory bath improvements are disclosed with various advanced controls and adaptations for thermal control as well as infection control.