**CUSTOMER NOTICE** Due to unforeseen circumstances caused by ill health, with much sadness we have decided to close Reef Lounge Aquatics. We would like to thank all our loyal customers, suppliers, family and friends who have been instrumental in growing the business and supporting us through our journey over the past 2 years. This was a very difficult decision for us to make and we would like to invite you all to a closing down sale which will begin this coming weekend. We look forward to seeing you all in the next few weeks. Best wishes The Reef Lounge team.

Oceamo DUO Calcium 1000ml in stock!

Regular price £14.99

A complete 2 Part dosing system, inorganic and ionically balanced.

DUO supplies all the essential elements required for a successful reef aquarium.
Extremely ionically balanced
Very stable 1 : 1 dosing
Raises and stabilises pH
Unique to Oceamo and its design is total controllability over any other method to date.

Very economical to use and a proven product throughout Europe and the UK for many years now.

Added concentrated directly or can be diluted if so required for the smaller aquarium use and or where higher accuracy is required with your dosing pumps.

Oceamo Duo is the most ionic balanced complete product you'll ever use and we all know stability is one of the major keys to a successful Reef Aquarium.

Oceamo DUO complete component 1
Oceamo DUO complete component 2

  • DUO is simple to use with only 2 solutions offering 1 : 1 dosage

  • DUO is very economical: the typical dosage is 10 ml per 100 l per day. 1 liter DUO contains 10 000 dKH units

  • DUO increases pH value and thus promotes coral growth

  • DUO also supplies strontium, boron, magnesium, potassium, fluoride, iodide, sulfate, bromide and rubidium proportionally to the aquarium

  • There is no ionic shift when using Oceamo DUO

  • The quality of DUO is meticulously checked in the Oceamo laboratory

  • Oceamo DUO can be optimally complemented by DUO Regulator. A & O 

  • DUO can be flexibly supplemented with DUO add-ons a source of phosphorus and nitrogen (optimal in case of nutrient deficiency)

Winter notice:

DUO KH is highly concentrated, so ingredients can crystallize at cold temperatures. DUO KH should therefore not be stored in cold temperatures.

​If crystallization has occurred (for example, during shipment), heat the DUO KH (for example, place it in the bath tub with hot water) and pan it back and forth until all ingredients have dissolved again or a microwave works very well too.

What is Oceamo DUO for?

​Oceamo DUO is a system for simple and effective supply of seawater aquariums with calcium and alkalinity (KH). These are the most important building blocks for the growth of stone corals in reef aquariums. In addition to Ca and KH, DUO also provides the important macro elements potassium, strontium, boron, magnesium, bromide, sulfate and the trace elements rubidium, iodine and fluoride to create an optimal environment in the aquarium for healthy growth.

What are the advantages of the Oceamo DUO system?

DUO is very easy to use: it consists of only two components, which are usually dosed in the same amount. DUO does not need to be diluted or dissolved before use.


The composition of DUO prevents ionic shift (at 1:1 dosage).

​The PH value is raised by DUO, which accelerates the growth of hard corals. By the use of DUO the use of CO2 scrubber to stabilize the PH can often become obsolete. This leads to lower operating costs.

​In addition to the "main parameters" of calcium and alkalinity, DUO doses many other substances: strontium, boron, iodine, fluoride, bromide, sulfate, potassium, rubidium and magnesium. As a result, these important water parameters are adjusted to coral consumption.

​DUO dispenses with an organic content: this allows the product to be diluted as required, and the dosing of DUO does not deprive the aquarium water of any oxygen.

​In our very own laboratory, all raw materials and products undergo a strict quality control (using ICP-OES and other methods). This enables us to guarantee the consistently high quality of our products.

How long can I get on with a liter of Oceamo DUO?

Oceamo DUO is very efficient: 10 ml will increase the alkalinity in 100 liter by 1° dKH. In an averagely populated aquarium, approximately 10 ml DUO is needed per day per 100 l.

 An 80-liter nano tank can be operated with 1 liter DUO for an average of 125 days.

In which container sizes is Oceamo DUO available?

DUO is available in 1 litre containers and 5 litre containers. For tanks over 500 l, we recommend the use of 5L containers. Our containers are spill-proof, and the 1000 ml containers are also equipped with a child safety lock.

How & when should Oceamo DUO be dosed?

DUO can be dosed manually or by a dosing pump. DUO Reef Care System 1 & 2 should be added with time delay (at least 10 minutes) at a high-flow point (e.g. the sump). It is best to divide the dosage into several individual portions to keep KH and Ca as even as possible.

Can the products be diluted? Does this limit the shelf life?

​For very small aquariums, it makes sense to dilute DUO before use in order to achieve a higher dosing accuracy.

​DUO can be easily diluted with osmosis water in any proportion, the durability is not influenced.

How often should alkalinity and calcium be measured and dosage be adjusted?

​We recommend to measure the alkalinity and calcium values every 2-3 days in the initial phase (after switching to DUO) and adjust the dosage accordingly.

Do you need help finding the right dosage? Please contact us, we are happy to help!

 Once established, alkalinity and calcium should be measured ideally every 1 to 2 weeks and dosage adjusted if necessary.

​Do all other water parameters, such as boron, strontium, potassium, magnesium, iodine, etc. remain within the optimal range due to the dosage of DUO?

​Each tank is different, which is why no product can permanently nail all water values to the set point. We have designed DUO to guarantee a basic supply, and so a critical lack of these items is highly unlikely. Nevertheless, the dosage is in an area where no unnatural enrichment is expected. It is recommended to run a water analysis in our laboratory every 3-6 months in order to be able to adjust the water parameters to the optimal value if necessary.

 Does DUO cause an ionic shift, or an increase in salinity?

DUO is designed in a way that all essential components of the seawater are added so no ionic shift should happen.

Due to the dosage of DUO, additional sea salt is produced, which increases the salinity. This should be taken into account for water changes.

 When dosing 1 liter of DUO, ~ 8.7 liters of seawater should be replaced with osmosis water to keep salinity constant.

 Example 1) In a 1000 liter tank, 100 ml DUO are dosed daily. In order to keep salinity constant, once a week 6 liters of water should be replaced by osmosis water

Example 2) In a 100 liter tank, 10 ml DUO are dosed daily. To keep the salinity constant, 0.6 l of water should be replaced once a week with osmosis water.

​With which products can DUO be supplemented?

A. We recommend supplementing the primary care of DUO with inorganic trace elements and organic nutrients (amino acids, carbohydrates).  This supply is ensured by the Oceamo Regulator A & O. ​Take a look at the product information on the Oceamo Regulators which are extremely cost effective and very efficient supplements and offers complete support of all that is required.

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