Seachem Reef Kalkwasser 500 gm

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). Many who use kalkwasser are quite successful with their marine systems and find it to be an effective way of maintaining calcium. However, it can be a difficult technique for the beginner to master. The carbonate alkalinity must be monitored and adjusted to ensure that it does not become depleted through chalk (calcium carbonate) precipitation. The magnesium concentration must also be monitored and maintained since precipitation of magnesium hydroxide (arising from excess hydroxyl ions) can lead to a change in the balance of the various buffer systems present which can result in drastic pH shifts. Additionally, magnesium is an essential component of seawater that is required by all corals. There will be an increase in the build up of chalk on substrate and plumbing surfaces which will require more frequent cleanings in order to maintain the proper functioning of the aquarium. If due care and diligence is paid to all of these factors, there is no reason one cannot maintain a successful reef system while using kalkwasser. 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.

Sizes: 250 gm,500 gm

Never add this product directly to the tank. Add 3 g (1 teaspoon) to 4 L (1 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 gallon*). Drip this solution into tank. Monitor pH and carbonate alkalinity. Adjust rate of addition to maintain a stable pH (8.3-8.4). HINTS: Adding 4 L (1 gallon*) of a saturated kalkwasser solution to 150 L (40 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. Avoid contact or breathing dust. Do not eat or get in eyes. In case of contact, flush area with water for 5-10 minutes. In case of eye contact, wash eyes with water immediately (5-10 minutes) and seek medical attention.

Compatibility

What it is. Very pure calcium hydroxide (limewater), used to maintain calcium at natural seawater levels while raising pH — without the alkalinity swing a straight carbonate buffer causes. How much alkalinity effect actually shows up depends on the tank’s evaporation rate and CO2 level.

Pack size. Same formula and directions at 250 g and 500 g.

Dosage & Directions

Mixing it. Standard solution: 3 g (1 teaspoon) dissolved into 4 L (1 US gallon) of water. Saturated solution (with pure/RO water): 6 g (2 teaspoons) into 4 L.

Dosing it. Drip the prepared solution into the tank — never add the powder directly — using only the clear supernatant and keeping any undissolved material out of the aquarium. Adjust the drip rate against pH, holding it between 8.3 and 8.4.

What to expect. Seachem’s own figure: one US gallon of saturated solution dosed into 150 gallons of tank water raises calcium by about 24 mg/L.

Handling. Causes burns — wear gloves and eye protection when mixing, avoid breathing the dust, and flush any contact area with water for 5 to 10 minutes.

Freshness & Storage

Every batch we dispatch carries a minimum of 6 months’ remaining shelf life. Store this product in a cool, dry place away from direct sunlight, with the cap or inner foil closed tightly after each use.

Returns & Replacement

Returns are accepted within 7 days of delivery, provided the item is unused and in its original packaging. Manufacturer-sealed items cannot be returned once the seal is broken, and sale-priced items are not refundable.

If your item arrives defective or damaged, message us on WhatsApp with your order number, or email us if you would rather, and we will replace it. Approved replacements are delivered within 3 to 5 business days. Transit damage is covered by insurance on every shipment. If tracking shows delivered but nothing reached you, tell us within 72 hours, which is the reporting window Indian couriers allow. Damage caused during installation or use is not covered; replacement spares for such cases are chargeable.

Full terms are on our Cancellation & Returns page.