Hach Environmental is excited to announce the release the new Series 5 platform of water quality instruments. This new platform offers Hach LDO (Luminescent Dissolved Oxygen) as a sensor option. With Hach’s industry-best LDO technology on a Hydrolab Series 5 sonde, you never have any DO membranes to replace, DO calibrations last longer than ever before, and the accuracy of your DO data is unmatched.