Home7. FAQ's and KnowledgebaseDissolved OxygenCan I still get LDO probes for the… Dissolved Oxygen Can I still get LDO probes for the Hach HQ10 and HQ20 meters? November 24, 2009 David Miller Can I still get replacement LDO probes for the Hach HQ10 and HQ20 meters? Hach LDO probe for HQ10 and HQ20 Yes, The Hach LDO probes and the Hach LDO Sensor caps are still available for the old HQ10 and HQ20 meters Please see the links for information and current pricing. The HQ10 and 20 have been replaced by the HQ30 and HQ40 meters which are available from Camlab. Please note that the sensor caps and the probes are not intechangeable with the new meters.