Brightwell Aquatics Alkalin 8.3 is a highly effective, multi-component alkalinity (KH) buffer and pH stabilizer formulated specifically for marine and reef aquariums. Unlike simple, single-source supplements like basic sodium carbonate, it utilizes an automated blending formula that actively safely locks your aquarium's pH at 8.3 while building up the necessary carbonate hardness.  
Key Features & Benefits
Automatic pH Capping: Continued dosing safely brings your pH up toward 8.3. Once it hits 8.3, the pH remains locked in place, and further additions will only increase your alkalinity (KH) without overshooting the pH.  
Supports Coral Skeleton Growth: It delivers a robust source of carbonates, which represent roughly 60% of the weight of aragonite—the mineral reef-building organisms and corals use to build their skeletons.  
Highly Concentrated: The solution is designed to be over 50% stronger than many competing alkalinity solutions on the market, giving you more value per dose.  
Ultra-Pure Formula: It is entirely free of unwanted phosphates, silicates, or organic material, ensuring you aren't fueling nuisance algae blooms. 
Available Formats: It is sold both as a convenient ready-to-use liquid solution (Alkalin 8.3) and as a concentrated powder mix (Alkalin 8.3-P) that must be dissolved in fresh water before addition. 

Basic Dosing Guidelines
Target Levels: It is generally recommended to keep a marine aquarium's alkalinity sitting comfortably between 7 to 12 dKH. Always measure your current levels with an accurate test kit before you begin dosing.
Powder Dosing (Alkalin 8.3-P): A baseline dose is typically 2 grams (approx. 1/2 teaspoon) dissolved into 8 ounces of fresh water per 20 gallons of aquarium water.
Important Safety Rule: Never pour the raw powder or heavily concentrated solution directly into the main tank or near sensitive livestock; dilute it first and add it slowly to a high-flow area like a sump.