Abstract: An anti-fouling submersible liquid sensor (100) is provided according to the invention. The anti-fouling submersible liquid sensor (100) includes a measurement chamber (102) including one or more liquid measurement sensors (121) and at least one chamber aperture (104), at least one gate (107), a gate actuator (128) configured to selectively move the at least one gate (107) between open and closed positions with regard to the at least one chamber aperture (104), and a radiation source (124) configured to inactivate at least a portion of a liquid sample in the measurement chamber (102). The anti-fouling submersible liquid sensor (100) is configured to admit the liquid sample into the measurement chamber (102), perform one or more measurements on the liquid sample, substantially inactivate biological material within the liquid sample with radiation from the radiation source (124), and hold the inactivated liquid sample until a next sample time.

Abstract: A sonde cleaning brush is disclosed that has a plurality of bristles extending from the brush surface. The bristles have a stiffener attached to the bristles causing the stiffness of the bristles to increase along the length of the brush while preserving the flexibility of the bristles perpendicular to the brush length. There may be one or more stiffeners attached to the brush bristles.