Brightwell Reef Code A is the calcium half of Brightwell's balanced two-part calcium and alkalinity system for reef aquariums. Dosed in equal measure with Reef Code B, it replenishes the calcium, strontium, and trace minerals that corals, clams, and coralline algae pull from the water as they grow, in the same ratio found in natural seawater. Round out the big three with Magnesion magnesium, and browse more Brightwell Aquatics reef care. How the Two-Part System Works Growing corals and other reef life constantly pull calcium and carbonate (alkalinity) out of your water. Reef Code A and Reef Code B replace them together, in balance: Reef Code A supplies calcium plus strontium and minor and trace elements. Reef Code B supplies the carbonates that make up alkalinity, your tank's buffering capacity. Used in equal amounts, the two keep calcium and alkalinity rising or holding steady together, just as they occur in natural seawater. Bring magnesium into range first (1,290 to 1,320 ppm) with Magnesion so calcium and alkalinity stay in solution instead of precipitating out. Features Calcium-bearing half of a balanced two-part calcium and alkalinity system Also supplies strontium and reef trace minerals Ionically balanced to natural seawater when dosed equally with Reef Code B Simplifies calcium and alkalinity maintenance Reef safe, with no phosphate or silicate Directions for Use Shake well before use and test your calcium level before dosing. Add 5 ml of Reef Code A per 25 gallons every other day, or as needed, to keep calcium in the 412 to 450 ppm range, and dose an equal amount of Reef Code B to hold alkalinity steady. Used this way, 250 ml treats up to 1,250 gallons. Adjust the dose up or down based on your test results and how quickly your tank consumes calcium. Before you start: bring magnesium to 1,290 to 1,320 ppm with Magnesion. Correct magnesium keeps calcium and carbonate from precipitating, so both stay available to your corals. Choose Your Size Size Best for 250 ml Nano and smaller reef tanks, or trying the Reef Code system. 500 ml Mid-size reef tanks with steady calcium demand. 1 L Larger or coral-heavy systems, with the best value per ml. Specifications Brand Brightwell Aquatics Product Reef Code A, calcium component Supplies Calcium, strontium, and trace minerals Use with Reef Code B (equal amounts), plus Magnesion for magnesium Best for Saltwater reef aquariums Available sizes 250 ml, 500 ml, 1 L Reef safe Yes Country of origin United States Recommended Pairings Reef Code B is the alkalinity half, dosed in equal amounts. Magnesion keeps magnesium in range so calcium and alkalinity stay stable. Brightwell Aquatics is the full brand lineup. Additives and supplements for more reef dosing options. FAQ Do I have to use Reef Code B as well? For a balanced system, yes. Reef Code A and B are designed to be dosed in equal amounts so calcium and alkalinity stay in the natural seawater ratio. Some tanks need slightly different amounts of each based on demand, so test and adjust. Why check magnesium first? Magnesium keeps calcium and carbonate dissolved. If magnesium is low, dosing calcium and alkalinity can cause them to precipitate out instead of feeding your corals. Hold magnesium at 1,290 to 1,320 ppm with Magnesion. Is it safe for corals and inverts? Yes. Reef Code A is reef safe and contains no phosphate or silicate. Dose to your test results rather than guessing. How much do I need? A rough starting point is 5 ml per 25 gallons every other day, but every tank is different. Test calcium and alkalinity regularly and adjust the dose to match your tank's uptake.
