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The Oceamo DUO System

Oceamo DUO is a supply system that optimally delivers your reef aquarium with  alkalinity and calcium

DUO offers many advantages in addition to this:

  • No dissolving or dilution necessary

  • DUO is simple: only 2 solutions, 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 DUO

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

  • Oceamo DUO is optimally complemented by DUO Regulator. DUO can be flexibly supplemented with DUO add-ons with 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.

Here are the most frequently asked questions about Oceamo DUO.

If you have further questions we look forward to your message!

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 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 does DUO last?

Oceamo DUO is very efficient: 10 ml increases the alkalinity in 100 liters tank water 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 l containers and 5 l canisters. For tanks over 500 l, we recommend the use of 5 l canisters. 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 KH and DUO Ca 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 once a week.

Do all other water parameters, such as boron, strontium, potassium, magnesium, iodine and co, 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?

We recommend supplementing the primary care by DUO with inorganic trace elements and organic nutrients (amino acids, carbohydrates). This supply is ensured by Oceamo Regulator A & O.

Click here for the Oceamo Onlineshop.

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