Stop relying on "Brine" measurements for your delicate reef ecosystem. Most industry-standard refractometers are calibrated for simple salt brine (NaCl) at 15°C, leading to an error of approximately 1.5ppt in a marine aquarium. The Red Starfish Seawater Portable Refractometer is specifically engineered for the unique ionic content of Natural Seawater (NSW), providing the absolute salinity accuracy required for sensitive SPS and LPS corals.
Standard refractometers are designed for the food industry (brine) at cold temperatures. The Red Starfish is purpose-built for the hobbyist:
Calibrated for Seawater (NSW): Uses a specialized algorithm for seawater rather than brine, ensuring your 35ppt reading is truly 35ppt.
Optimized for Reef Temperatures: Calibrated at 25°C (77°F)—the standard operating temperature for tropical reefs—eliminating the need for complex conversion charts.
High-Resolution Display: The scale is focused specifically on the 0–40ppt range, offering a much larger and clearer visual display than standard 0–100ppt "all-purpose" meters.
Integrated ATC (Automatic Temperature Compensation): Ensures accurate readings even if your room temperature fluctuates between 10°C and 30°C.
Direct Absolute Salinity: No need for seawater compensation factors; the number you see on the lens is the actual salinity of your tanks.
Laboratory-Grade Optics: Features a high-quality glass prism and an adjustable eyepiece for a sharp, high-contrast boundary line.
Durable & Portable: Includes a protective hard-shell carry case, a calibration screwdriver, a precision pipette for easy sampling, and a distilled water calibration Fluid.
| Feature | Details |
| Calibration Algorithm | Natural Seawater (NSW) |
| Standard Temperature | 25°C / 77°F |
| Measurement Range | 0 – 40 ppt / 1.000 – 1.030 S.G. |
| Accuracy | +/- 1ppt / 0.001 S.G. |
| Compensation | Built-in ATC |
| In the Box | Refractometer, Hard Case, Pipette, Microfiber Cloth, Distilled Water Calibration Fluid. |
Clean the prism with RODI water and dry with a soft cloth.
Place 2-3 drops of your aquarium water (or VASTOCEAN 35ppt Calibration Fluid) on the prism.
Close the cover and wait 15 seconds for the ATC to equalize the temperature.
Look through the eyepiece toward a light source and read the result on the high-resolution scale.
