- The calcium-bearing component of a two-part method for dosing calcium and carbonates (the substances largely responsible for increasing alkalinity (”buffering capacity”)) in the same ratio as that found in natural seawater.
- Ionically-balanced with respect to natural seawater concentrations of calcium and carbonates when used in equal amounts with Reef Code B.
- Benefits reef-building organisms such as corals, clams, calcareous algae, etc.
- Simplifies calcium and alkalinity maintenance.
- Stronger than most competing products.
- Contains no phosphate, silicate, or organic material.
- Formulated by a marine scientist.
This method of calcium and carbonate supplementation is advantageous to hobbyists interested in a simple and effective means of providing the very elements and molecules required for growth of reef-building organisms such as corals, clams, and their allies. Corals and other reef-building organisms require adequate and stable available calcium and alkalinity if they are to thrive, regardless of how perfect the remainder of their environment is. Under most conditions, the mineral that is secreted as skeletal material is known as Aragonite, composed mostly of carbonate and calcium by weight. Reef-building organisms must extract these substances from the surrounding water in order to secrete new skeletal material for growth. By maintaining the same ratio of calcium ions and carbonates in an aquarium as that found in natural seawater, these organisms have the necessary building blocks available in the proper proportions, even if the hobbyist chooses to maintain higher concentrations of these substances.
For maximum effectiveness of the Reef Code method, the magnesium concentration in reef aquaria should be adjusted to, and maintained between, 1,290 - 1,320 ppm before using these products (alone or together) or any other calcium and alkalinity products. Doing so helps prevent unwanted precipitation between calcium and carbonate ions. Additional information on this subject is available on our website and on the label for Brightwell Aquatics Magnesion.
The rate at which calcium and carbonates are extracted from the water is determined by the stocking density of reef-building livestock, type of lighting, and other conditions; therefore, each aquarium will have different requirements for the rate of supplementation. Once the rate of calcium uptake in the aquarium has been determined, the proper dosing rate of this product can be easily calculated.
Instructions and Guidelines
Basic: Shake product well before using. Add 5 ml (1 capful) of product per 25 US-gallons of aquarium water every other day or as needed to maintain the calcium concentration within a range of 412 - 450 ppm. When used in this fashion, 250 ml treats up to 1,250 US-gallons (4,732 L). When used in equal amounts with Reef Code B, the calcium and carbonates being added are in the same ratio found in natural seawater. Do not mix products in the same container; this will cause the active components to precipitate and become ineffective. Allow 60 seconds to pass between dosing Reef Code A and B.
Advanced: Determine the calcium concentration in the aquarium using an accurate test kit before supplementing. Shake this product well before each use. Each ml of Brightwell Aquatics Reef Code A will increase the concentration of calcium (“[Ca2+]”) in 1 US-gallon (3.785 L) of water by approximately 16 ppm. If the initial [Ca2+] in the aquarium is below 412 ppm, add this product at the maximum rate of 5 ml per 10 US-gallons daily until the desired calcium concentration is attained, then dose daily or weekly as needed (see below). Note that each aquarium has different requirements for calcium and carbonates (which largely constitute Alkalinity or Buffering Capacity, hence pH-stability); therefore, it is not uncommon for unequal amounts of Reef Code A and B to be required for obtaining and maintaining the desired calcium concentration and alkalinity. To determine the daily dosing rate for calcium maintenance: estimate the volume of water in the entire aquarium system; divide the daily decrease in [Ca2+] by 16; multiply this number by the volume of water in the system to get the daily dosage required (ml) to maintain a stable [Ca2+].
Caution: May cause eye or skin irritation. Flush with water for 15 minutes if in eyes, seek medical attention if irritation persists. Keep out of reach of children. Not for human consumption.
Calcium (min) 1,774 mg/oz. (60,000 ppm)
Magnesium (min) 42 mg/oz. (1,500 ppm)
Strontium (min) 36 mg/oz. (1,200 ppm
Purified water, Calcium chloride, Magnesium sulfate, Strontium chloride, Magnesium chloride
Brightwell Aquatics Aquarium Supplies
The goal of Brightwell Aquatics is to provide the absolute highest quality, scientifically-sound products and customer service of any aquarium water care manufacturer, and to do it all in a straight-forward and honorable fashion. All Brightwell products are formulated by marine scientists with a passion for the aquarium hobby. They utilize the highest purity ingredients in concentrations that provide the most use to hobbyists. Nearly all Brightwell Aquatics products are over 99.9% pure. The usage guidelines of Brightwell Aquatics products are written in plain language but the company is always available to answer consumer questions. All products are lot numbered for quality control and customer service.
We ship 99% of the products we carry for free within the contiguous United States using a mix of economy methods including USPS First Class Mail, SurePost and UPS Ground. Your order will arrive in 5-7 business days.
Over 90% of our members receive their orders within 2 business using UPS Ground. Upgrade from free economy shipping to UPS Ground for only $4.99—or spend $199 and we’ll upgrade you automatically!
Expediated shipping services are available for most products if you are in a hurry. Get guaranteed delivery in 2 business days, 1 business day, or next day by 10:30 am. Costs vary by location.
Same-day shipping is available Monday-Friday for most products—place your order by 10 am PST. Pre-ordered and back-ordered items do not qualify, nor do drop-shipped, live, or frozen shipments.
Learn More About Shipping
Return any new and unused item within 60 days for a full refund. Having difficulty with a product? Contact us to speak with an aquarium expert. If you need a replacement, fill out this form.
A small segment of the 180+ brands we carry require that customers contact them directly if/when problems arise. You can view the full list of those brands and get their contact info here.
Marine Depot is an authorized reseller for every product we carry. That means when you buy aquarium supplies from us, your products are not only backed by our own 60-day return policy, they also carry full factory warranties, where applicable. Some items have a 1-year warranty, others have limited lifetime warranties. Warranty coverage varies from manufacturer to manufacturer, so please read the product description of the item(s) you are considering thoroughly for details or contact us if you have warranty questions.
Learn More About Returns
Rack up reward points to earn discounts on future purchases! You can earn reward points by creating an account, writing reviews, referring friends, subscribing to our newsletter, buying products, and more!
- Most Products
Earn 5 reward points for every $1 you spend to get 5% cash back
- Marine Depot, AquaMaxx, Accel Aquatics, and Korallin
Earn 6 reward points for every $1 you spend to get 6% cash back
- Aqua Illumination, EcoTech Marine, Nano Box, Neptune Systems, NYOS, Oceanbox Designs, Pax Bellum, and Reef Glass
Earn 1 reward point for every $1 you spend to get 1% cash back
You can also get bonus reward points by purchasing select items during special sales and promotions.
Learn More About Rewards