AquaMedic Calcium Reactors : Calcium reactors dose a 24 hour stream of calcium ions and carbonate ions into your reef system. This is the ideal ion pairing that the popular two-part liquid additives offer, though at a much higher long-term cost, and it is up to you to dose it daily and dose it correctly. Calcium reactors automate this process and relieve you of the daily measuring and dosing burden. Aqua Medic Calcium reactors house a generous portion of pure Hydrocarbonat media which is dissolved by the controlled dosing of CO2 gas to lower the pH within the unit.
- Aqua Medic Calcium Reactor 1000
- Aqua Medic Calcium Reactor 400
- Calcium Reactor Maxi 5000 by Aqua Medic

- Aqua Medic Kalkwasser Reactor : Kalkwasser is the original marine calcium supplement/alkalinity buffer and nothing has proven better for promoting beautiful coralline algae growth. Kalkwasser also binds phosphates, an attribute no other calcium addition can boast.
The Kalkwasserreactor greatly reduces the mess and hassle of using kalkwasser. Coupled with an automatic top-off system, like our Niveaumat, fresh water is pulled through the reactor “on-demand” to compensate for evaporation in your system. The incoming fresh water is pump-mixed in the reactor with the cached supply of undissolved Kalkwasserpowder.
The micron-filtered mixing action ensures a steady supply of clear, saturated kalkwasser solution, to be fed slowly to the system via a top up system such as the Niveaumat.
Filling is easy with a capped port atop the unit through which a re-fill of Kalkwasserpowder slurry can simply be poured. With the robust and convenient drain valve, nested below the settling cone, flushing the unit of precipitate between fillings is easy and mess-free.

- Aqua Medic Kalkwasser Stirrer 1000
- Kalkwasser Stirrer 5000 by Aqua Medic
Simple and reliable way to add kalkwasser to your aquarium.
Kalkwasser might be old-school but these uniquely “revolutionary” stirrers bring the legendary calcium and alkalinity solution into the new millennium.
It would not be overstating things to say that kalkwasser has enormous benefits for captive reef aquariums.
Kalkwasser powder is an excellent source of calcium, hydroxide ions to buffer alkalinity, an unmatched ability to encourage coralline algae growth, and it precipitates phosphates out of your system water!
Why in the world then wouldn’t we all be using it? Primarily it is the mess and hassle of preparing it in small batches, for use as top-off water, which eventually becomes disheartening.
The new Kalkwasser Stirrer delivers the freshest possible kalkwasser solution, on-demand, in line with your automated top off system, like the Aqua Medic Niveaumat. And it does this for up to two weeks with no mess, no hassles, and no problems. The gentle stirring action is perfectly designed to mix incoming top-off water directly into the gently spinning slurry of undissolved Kalkwasserpowder at the bottom of the Kalkwasser Stirrer’s reaction chamber.
Above the slurry, the top-off water rises into a fresh, clear volume of saturated kalkwasser solution where it is pulled, as needed, into your reef tank.
Now there is no excuse not to take advantage of all the benefits that come with dosing kalkwasser. The Kalkwasser Stirrer is a must have and partners beautifully with an Aqua Medic Calcium reactor to deliver extraordinary results in even the most demanding SPS coral displays.
1 lb. of kalkwasser powder included.

RX-1 Calcium Reactor by AquaC : The RX-1 calcium reactor represents the pinnacle in reactor technology available today. We've combined all the features an advanced reef hobbyist is looking for into a compact package that is easy to use and maintain. No more messing with finicky settings or inconsistent results, the RX-1 is a solid performer that will give you years of trouble-free service.
The RX-1 is rated for reef tanks up to 400 gallons in size.
Features and Specifications:
• 8.25" x 9" footprint
• 16" tall
• Box design holds more media than cylinder-style reactors
• Reverse flow
• Recirculating CO2
• pH probe holder
• Eheim 1250 pump
• John Guest Speedfit fittings throughout
• Sch. 80 PVC and unions
• Large union for quick and easy media addition
• SMC valve for precise effluent control
• Media not included
Quick Facts about the RX-1
The Eheim 1250 pump included with the RX-1 sets the standard for flow and efficiency - no other reactor in its class offers such a powerful and reliable pump. The Eheim carries a 2 year warranty.
By utlizing a box design, we're able to make the most efficient use of space (which is often at a premium under an aquarium). The RX-1 is large enough to hold an entire container of Carib Sea ARM media!

Coralife Calcium Reactors : Coralife Calcium Reactors monitor and stabilize the calcium levels in your aquarium. A great addition to any reef tank.
- Coralife Calcium Reactor 250
- Coralife Calcium Reactor 500

K2R Calcium Reactor : Complete with recirculating pump. These calcium reactors raise alkalinity to 11 -12 DKH and maintain constant calcium levels @ 480-500 ppm by slowly dissolving aragonite. This is the answer to fluctuating pH, alkalinity and calcium levels.

Knop Calcium Reactors : Because of their reliability, the stable construction, the easy operation, and the affordable price Knop Calcium Reactors have become one of the most frequently sold calcium reactors worldwide, These are market leader in the USA and Japan.
- Knop Calcium Reactor C
- Knop Calcium Reactor HD
- Knop Calcium Reactor S IV

Korallin Calcium Reactors : Four models available: Korallin C1502, Korallin C3002, Korallin C4002, & Korallin C10002 . In the coral reef tank, the calcium hydrogen carbonate content is an important parameter on which the lime formation and therefore the growth of the corals at decisive measure depends.
It takes strong influence as a main component of the bumper system to the pH-value. Without suitable countermeasure accompany very soon it to lime lack combined with growth reduced at least strongly lime consuming organisms.
The KORALLIN calcium reactors allow in simple, elegant way and with high efficacy to produce calcium hydrogen carbonate including the necessary balance carbonic acid and the fish-tank water continuous lead. It becomes ready for immediate use operating with integrated Eheim pumps (ceramic axis + carbon bearings) with special substrate supplied to the connection to usual CO2 devices, is sufficient for tanks up to 1500l and in a filled manner highest quality control requirements.
On account of its small overall height (approx. 400mm) it can become readily set up under the fish-tank, also into the filter box!

- Korallin C 1502 Calcium Reactor
- Korallin C 3002 Calcium Reactor
- Korallin C 4002 Calcium Reactor
- Korallin C 10002 Calcium Reactor

Octopus Calcium Reactors : Octopus Calcium Reactors are constructed with high quality Cell Cast Acrylic materials and SCH-80 Hard PVC pipes and JG fittings.
Great Value and quality construction.
- Octopus Reverse Flow Calcium Reactor 6.5" Dual Chamber with pump, by CoralVue
- Octopus Calcium Reactor CR-140 by CoralVue

Precision Marine Calcium Reactors : Compact Size Calcium Reactors with Clear acrylic bubble counter High-Quality threaded check -valve Silent Eheim water pump w/Two-Year warranty Open access to reaction chamber - Micro-adjustable polypropolylene valve - All Quick-Release fittings throughout - CO2 mixes with mater pump intake - Valve is located at top to purge excess CO2.
- CR 422 Professional Calcium Reactor
- CR 622 Professional Calcium Reactor
- CR 622D Professional Calcium Reactor
- KR 620 Professional Kalkwasser Reactor
- EF 1 Calcium Reactor Effluent Chamber

Schuran Calcium Reactors : The Jetstream is a new type of calcium reactor which uses a gas/water separator and offers optimum management of carbon dioxide. Every bubble is used and any CO2 remaining is dissolved. The water inside the calcium reactor is circulated by a centrifugal pump and the water being saturated with carbon dioxide creates an acidic medium in which the coral sand is dissolved as calcium hydrogen carbonate.
- Schuran Jetstream 1 Calcium Reactor
- Schuran Jetstream 2 Calcium Reactor
- Schuran Jetstream Pico Calcium Reactor

GEO Kalkwasser Reactor : All Cell Cast acrylic construction
* Side mount pump
* Easy fill top for kalk replacement
* Drain valve for testing and filling
* Dependable Maxi-Jet stir pump
* Use with your top off system to replace evaporated aquarium water with kalkwasser
* 7x12 foot print, 22" tall
The world famous GEO kalkwasser reactor!
Our kalk reactors are fabricated using only the finest cast acrylic materials and high quality fittings.
Designed with the user in mind, we feel these are by far the easiest reactors on the market to install, operate and maintain. Easy fill fitting on the lid for adding kalkwasser as needed. You only need to remove the lid for cleaning the reactor.
Drain valve allows you to lower water level in the reactor when adding fresh kalkwasser. You simply remove water from the reactor into a container of kalkwasser, stir it into slurry and pour it back into the reactor through the easy fill opening.
The dependable Maxi Jet stir pump mixes the powder in the chamber; there is no chance of powder exiting the reactor, even if the dosing is pumping water through the reactor as the pump is mixing.

GEO Calcium Reactors:

- 618 Calcium Reactor by GEO
- 624 Calcium Reactor by GEO
- 818 Calcium Reactor by GEO:
* All cell cast acrylic construction
* Clear lid to view proper O-ring seal
* Key hole slot for lid removal
* Micro ball valve effluent control
* Pan World external pump, bolted to base plate
* pH probe port in lid
* pH probe adapter included
* Auto fill bubble counter
* 13 x 14 foot print, 24" overall height
* Holds 12 pounds of media, we recommend large grain schuran type
* Well suited for Large SPS reef displays or commercial holding systems
The world famous GEO calcium reactor!
Our reactors are fabricated using only the finest cast acrylic materials and high quality fittings. Designed with the user in mind, we feel these are by far the easiest reactors on the market to install, operate and maintain. Bottom up flow of water captures free CO2 and draws it back into the pump. This means less gas in the reactor and less gas in the effluent. There is no need for a second single pass chamber with our design.
These reactors include all of the fittings and tube required for normal installation. The user will need to supply the media, CO2 equipment and feed pump.

Vortex Dual Chamber Calcium Reactor by CoralVue : The Vortex Dual Calcium Reactor is designed for marine and African cichlid aquariums.
It raises the carbonate hardness and realises calcium ions that prevent water from accidification.
The flow path design includes double tier of tubular material and vortex plates that promote CO2 dissolution.
Directions:
- Install the equipment accordin to the instruction. Reactor can be hang along the edge of the tank verticaly, or placed horizontaly inside the stand.
- Fro tanks up to 55 gal. CO2 supplie is not necessary. Calcium will be released just by water circulation.

Calcium Reactor Media

A.R.M. Calcium Reactor Media, 8 lbs. by Caribsea: ARM Calcium Reactor Media By Caribsea is A complete reactor media containing not only calcium and carbonate, but essential trace elements as well. In fact ARM Calcium Reactor Media By Caribsea has nearly 50 times the strontium of other brands (7,390 ppm) A.R.M. is processed for immediate use, no rinsing required, and has double the surface area of regular aragonite. Precision grading (2-3mm) allows for maximum carbon dioxide penetration, and the exclusion of gastrpod shells ensures the lowest phosphate (less than 1/10 of 1 ppm) and silica (about 1/2 that of other brands) content. This grading also carries in the highest concentration of Halimeda incrassata, an aragonite so pure it has been used as a laboratory standard. ARM Calcium Reactor Media By Caribsea has the highest solubility of any reactor media available (metastable at 8.2), so CO2 consumption is much lower.
Container Size: 8 lb.

Aqua Medic Hydro Carbonate Calcium Reactor Media : Aqua Medic Hydrocarbonat is a pure natural product, free of impurities for use within our Calcium reactors.
Aqua Medic Hydrocarbonat also has uses as a substrate in African cichlid systems or in bypass filters to raise the pH of Calciumreactor effluent. A natural calcium-carbonic acid equilibrium is created in all systems with an alkaline pH value.
In our Calcium reactors supplied with CO2, the Hydrocarbonat is completely dissolved into calcium carbonate, becoming available for assimilation by hard, and many soft corals, sponges, echinoderms, etc.
Aqua Medic Hydrocarbonat is available in Medium and Course grain size (3-5mm).
For use in Calcium reactors, in hardening bypass filters, and as substrate in Malawi/Tanganyika exhibits.

KORALith Pure Calcium Carbonate, 15lbs. : KNOP KORALlith is a natural and phosphate-free calcium granulate that originates from fossilized marine habitats.
It consists of pure calcium carbonates at almost 99 %.
Because of its purity and the associated minerals and trace elements KNOP KORAL lith calcium carbonate media is perfect as a substrate for calcium reactors, filter material and for many other purposes in the reef aquarium hobby.
Container Size: 15 lbs. Media Size: 2-2.5 mm

Kalkwasser Reactor Media

Kalkwasser Mix 450 gr. by Kent Marine : KALKWASSER MIX provides bio-available calcium for lush growth of purple, pink and green calcareous algaes, snails, hard tube worms and clams.
Corals will open more and stay attached to their skeletons better, with regular use. Phosphate & nitrate free!
Contains no gluconates, EDTA, or other organics to raise DOC levels, as many competing products do. This product is the original European Method that has never been equaled for calcium addition to a Reef System! It will provide long term results that no other supplement will!
It requires a little more work, but so does anything that is really worthwhile!
KALKWASSER MIX can be used with Kent Marine Concentrated Liquid Calcium or TURBO CALCIUM for maximum results.
Strontium addition via use of Kent Marine Strontium & Molybdenum Supplement or TURBO STRONTIUM is absolutely necessary, as well.
Use of Coral-Vite, and Essential Elements are beneficial, as well.

Kalkwasser Powder 400 gr. by AquaMedic : High purity kalkwasser powder.
Kalkwasserpowder, when mixed with your top-off water to create a kalkwasser solution, represents one of the oldest methods for supplying calcium to, and buffering the alkalinity of, marine aquariums.
With generations of improved understandings of the biology and chemistry of our hobby, and a long lineage of technological improvements between us and the first use of kalkwasser you might wonder why it is still around.
Certainly it still has a place in the arsenal of so many hobbyists because it is a great source of calcium ions and alkalinity-buffering hydroxide ions.
Kalkwasser has the ability to accelerate the growth of beautiful coralline algae, while precipitating phosphates from the system, and it is exceptionally inexpensive, too.
Until recently kalkwasser was, however, difficult and laborious to implement.
Thanks to the introduction of the Kalkwasserreactor and Kalkwasser Stirrers by Aqua Medic, kalkwasser is now trivial and mess-free to incorporate into your calcium and alkalinity regiment.
For reef systems with demanding populations of clams and stony corals, the use of a Kalkwasser Stirrer in conjunction with a Calciumreactor can deliver remarkable results.

Seachem Reef Kalkwasser 500 ml. : Reef Kalkwasser Powder 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 the 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, my prefer to use other less involved methods for maintaing proper ionic concentration levels. (see right)