D-D H2Ocean Refractometer
$70.00
The D‑D True Seawater Refractometer is a precision, handheld salinity instrument calibrated specifically for natural seawater, not brine—making it far more accurate for reef aquariums than standard hobby refractometers. It solves the long‑standing problem that most refractometers are designed for sodium‑chloride brine, which reads incorrectly when magnesium, calcium, and other seawater ions are present. Below is a structured, evidence‑based overview grounded directly in manufacturer and retailer data. 🧠 Identity & Purpose Product: D‑D True Seawater Refractometer Function: Measures true salinity and specific gravity using refractive index calibrated for natural seawater. Why it matters: Standard brine‑calibrated refractometers misread seawater by ~1.5 ppt at 35 ppt because seawater’s refractive index differs from pure NaCl brine. 🔍 Key Features True Seawater Calibration Scale is engineered for the refractive index of natural seawater, giving accurate readings without conversion factors. 0–40 ppt High‑Resolution Scale Focuses on the reef‑relevant 30–40 ppt range. Offers 2.5× the resolution of typical 0–100 ppt refractometers. Auto Temperature Compensation (ATC) Internal bimetal strip adjusts the reading scale as instrument temperature changes. Ensures accurate readings once the sample equilibrates to the refractometer’s temperature. Copper Internal Body Conducts heat faster than aluminum or plastic, improving ATC accuracy and speed. ⚙️ How It Works Measures refractive index, not salinity directly. Because refractive index changes with temperature, ATC compensates automatically. Once calibrated at 20°C (68°F), it provides accurate readings across typical room temperatures. 🧪 Calibration & Use Calibration temperature: 20°C (68°F). Best calibration fluid: 35 ppt seawater calibration solution. Alternative: RO/DI water for zero‑point calibration (purity must be ensured). Lighting: Use a daylight‑like light source for best clarity. 📦 Specifications Scale: 0–40 ppt salinity Measurement: True seawater salinity & SG Body: Copper internal construction ATC Range: Approx. 10–30°C (per retailer documentation) 🐠 Why Reefkeepers Choose It Eliminates brine‑based salinity errors Faster temperature stabilization Higher resolution in the reef‑critical range More accurate long‑term stability for SPS/LPS systems