A second cooling method uses a pump and rubber tubing to circulate water drawn from an ice bucket in a closed loop. Although this method conserves water and limits spillage in the event of malfunction, the bucket must frequently be refilled with ice, requiring constant vigilance to avoid overheating of experiments. In addition, the ice-cold water can cause laboratory equipment to “sweat” and the bucket, occupying significant laboratory floor space, poses a trip hazard. Some institutions have purchased electric refrigeration units to provide cooling water. However, these units are large, expensive, noisy, inefficient, create vibration and reject a substantial amount of heat into the room.