Reef Kalkwasser™ is a pure calcium hydroxide with unsurpassed purity and solubility characteristics. Calcium hydroxide is used to prepare limewater (kalkwasser) solutions that will maintain calcium concentrations at natural seawater levels. Kalkwasser solutions maintain calcium directly and carbonate alkalinity indirectly. However, its capacity to perform these functions is dependent on evaporation rate and CO2 concentration. If these two factors are insufficient you can provide additional calcium with Reef Advantage Calcium™, Reef Complete™, or Reef Calcium™, and carbonate alkalinity with Reef Builder™ or Reef Carbonate™ (do not mix these directly with a kalkwasser solution).
While Reef Kalkwasser™ is a high purity and economical limewater mix, the beginner, or someone with not as much time to devote to their system, may prefer to use other less involved methods for maintaining proper ionic concentration levels.
Directions for use:
Never add this product directly to the tank. Add 3 g (1 teaspoon) to 4 L (1 US gallon) of water and mix to dissolve. If using pure water, a fully saturated solution is prepared by adding 6 g (2 teaspoons) to 4 L (1 US gallon). Drip this solution into tank. Monitor pH and carbonate alkalinity. Adjust rate of addition to maintain a stable pH (8.3–8.4). Notes: Adding 4 L (1 US gallon) of a saturated kalkwasser solution to 150 L (40 US gallons) will raise calcium by 24 mg/L. Always use the clear supernatant (top solution) only and do not allow undissolved material to enter the aquarium. Keep this container tightly closed when not in use and minimize solution/air contact to avoid calcium carbonate formation/precipitation.
Seachem Laboratories, Inc. was established in 1980 by Dr. Leo G. Morin. Seachem moved into a state of the art 110,000 square foot facility in Madison, Georgia marking their 25th anniversary in the industry in 2005. This facility includes production and research laboratories, manufacturing, inventory, shipping, and office space.
Most orders under $29 ship for only $2.99 using a mix of economy shipping methods including UPS Ground, USPS First Class, and/or SurePost. Your order will be delivered in up to 7 business days after it ships out.
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 up to 7 business days. Just spend $29 or more!
Over 90% of shoppers receive their orders within 1-2 business days. Upgrade from free economy shipping to faster shipping for only $2.99—or spend $250 and we'll upgrade you automatically!
Expedited 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 10:30 am PST. Pre-ordered and back-ordered items do not qualify, nor do drop-shipped, live, or frozen shipments.
We ship live plants, live foods, and frozen foods within the contiguous United States. Each of these categories is subject to its own $19.99 flat-rate shipping fee to cover the special packaging and/or expedited shipping costs required to ensure safe delivery. Orders with 12+ live plants ship free!
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.
We are unable to accept returns of Digital Aquatics, Neptune Systems, Vertex Aquaristik, Aqua Illumination (AI), EcoTech Marine, GHL, or Seneye products once the manufacturer's packaging seals have been broken.
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.
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!
You can also get bonus reward points by purchasing select items during special sales and promotions.