Product Details Smallest CTD on the market: The DST CTD Data Storage Tag measures and records salinity, temperature, and depth. Size: 50 mm in length x 15 mm in diameter. It is a self-contained CTD data logger that is user programmable to log data at specific sampling intervals. Collected data is displayed in a graph and table with a time stamp for each measurement. Application: Designed as a fish archival tag for migration studies of fish and marine animals. Enables scientists to gain valuable information on migration routes and behavioral patterns over long periods. The tag is externally attached to the animal due to the salinity sensor, which consists of two conductivity cells. Wide salinity range, low to high conductivity: Captures conductivity from 2 to 68 mS/cm. Low conductivity range (0.1–6 mS/cm) is also available, ideal for brackish water. Depth sensors from shallow water to deep ocean: Can be calibrated to 2,400 meters, with tolerance up to 2,500 meters. Other ranges: 150m, 500m, 1200m, 2400m. Tag holder kit: Available for easier and safer attachment to fish, increasing safety for the animal. Custom text on housing: Tags can have customized text for recapture purposes, important for commercially fished species. Key Features Smallest CTD data storage tag on the market Long battery life - up to 5 years Depth sensors for shallow to deep ocean Tag holder kit for external fish tagging User defined text on the housing Conductivity Sensor Conductivity sensor electrodes are located inside a small cup at the end of the logger housing. Pressure sensor for depth measurements is located at the membrane; temperature sensor is close to the membrane. Conductivity ranges available: 2-68 mS/cm and 0.1-6 mS/cm. Using the Logger Supported by SeaStar software and a Communication Box (purchased with first order). Programming: Place tag in Communication Box, connect via USB to PC, set start time/date and sampling interval in software. Sampling: Single or multiple intervals (up to 7 different intervals). Memory and battery life calculations are automatic in the software. Data upload: After recapture, insert tag into Communication Box and upload data to software. Data is displayed graphically and in tables, exportable to other programs. Battery life: Several years depending on usage and sampling interval. Battery life estimation is reported upon connection. Accessories Communication Box: Interface between DST and PC for starting logger and retrieving data. SeaStar software: For Windows, displays data graphically and in tables, exportable to other programs. Plate Holder Kit: For external attachment, includes wire fasteners, plastic plates, and silicone pads for comfort and safety. Available for centi and milli sized loggers. Capsule Holder Kit: Plastic capsule with holes for water flow, includes wire harness, plastic plate, and silicone pads. Available for all logger sizes. Floating Device: Available in different sizes for internal and external tagging, can be coated or painted for visibility. Documentation SeaStar Quick Start Guide 2025 (PDF) CTD battery life specifications (PDF) Technical Specifications Sensors: Conductivity (salinity), temperature, pressure Size (Diameter x Length): 15 mm x 50 mm Maximum Diameter: 18 mm at the closure end Housing Material: Alumina (Ceramic) Weight (in Air/in Water): 21g/13g Data Resolution: 12 bits Conductivity Ranges: 2-68 mS/cm (wide), 0.1-6 mS/cm (low) Conductivity Resolution: 0.03 mS/cm (2-68 mS/cm), 0.003 mS/cm (0.1-6 mS/cm) Conductivity Accuracy: +/-1.5 mS/cm (2-68 mS/cm), +/-0.15 mS/cm (0.1-6 mS/cm) Salinity Range: Depends on conductivity and temp. range Salinity Resolution: 0.02 PSU (2-68 mS/cm), 0.002 PSU (0.1-6 mS/cm) Salinity Accuracy: +/-1 PSU (2-68 mS/cm), +/-0.1 PSU (0.1-6 mS/cm) Temperature Range: -1°C to +40°C (30°F to 104°F) Temperature Resolution: 0.032°C (0.058°F) Temperature Accuracy: +/-0.1°C (0.18°F) Temperature Response Time: 20 sec (63% time constant) Standard Depth Ranges: 150m, 500m, 1200m, 2400m Depth Resolution: 0.03% of selected range Depth Accuracy: +/-1% of selected range Depth Response Time: Immediate Memory Type: Non-volatile EEPROM Memory Capacity: 87,217 measurements per sensor Memory Management: Custom programming Measurement Interval: User specified in seconds, minutes, or hours Minimum Measurement Interval: 1 second Multiple Intervals Option: Up to 7 different intervals Data Retention: 25 years Clock: Real time clock, accuracy +/-1 min/month Communications: Communication Box, wireless transmission when DST sits in the box, USB connection to PC Attachment Hole: 0.9 mm diameter Battery Life: 5 years (for 10 min sampling interval) Replaceable Battery: No *Based on conductivity full scale accuracy at 24°C.** For sampling interval of 10 minutes.Warranty: 12 months.Specifications may change without notice.