Oceanography CTD used and design by UPCT Mar Menor research group. A CTD device’s primary function is to detect how the conductivity and temperature of the water column changes relative to depth. This CTD obtain the values of colored dissolved organic matter (CDOM), Phycoerythrin (PE) and Chlorophyll (CHL). Currently using a master-slave communication. An Arduino is doing the slave, and the mastering task its doing for other devices, like phone or laptop.