Abstract: A circulating bath (10) including a heater (18) configured to heat a fluid (34) in a reservoir (22). The heater (18) is configured to be operatively connected to a source of power (50) by a control circuit (39) operatively coupled to the heater (18). First and second fluid level sensors (14) (16) are operatively coupled to the control circuit (39), and provide signals indicative of a low fluid condition in the reservoir (22). The control circuit (39) is configured to receive the signals from the fluid level sensors (14) (16), and disconnect the heater (18) from the source of power (50) in response to receiving a signal from either of the first and second fluid level sensors (14), (16) indicative of a low fluid condition.

Abstract: A dual parallel underdrain lateral for use in a filtration system having a filtration media includes a primary conduit extending along the underdrain lateral, which has a plurality of metering orifices for providing gas and liquid thereby; a secondary conduit, where the secondary conduit has a plurality of dispersion apertures in an upper side thereof to deliver the gas and liquid from the secondary conduit to the filtration media; and at least one gas conduit extending along the underdrain lateral, where the at least one gas conduit is connected to a gas source and is configured to provide the gas from the gas source directly to the primary conduit, or the secondary conduit, or any combination thereof.