Reef Tank Dosing: How to initiate and control coral growth… Calcium, KH, Magnesium, Amino Acids… Are you Balling Bruh?

Reef tank dosing is a popular topic regularly discussed in store with our reef tank customers.

Here at Aquatech we use a specific approach to dose our tanks with everything that the corals need to build healthy coral skeletons and luscious fleshy polyps.

So… What do we mean when we say dosing in a reef tank?

Reef tank dosing is a method of supplementing corals with the necessary elements for coral growth, providing the building blocks for them to build a calcium carbonate skeleton on which to grow. The ‘Balling Method’, as it is also commonly referred to, was developed in 1994 by Hans Werner-Balling, as published in the technical journal of Aquaristics, and is one of the easiest and most popular methods, used all over the world in reef aquariums by hobbyists and professionals. It is tried, tested and has many minor adaptations which have assisted many reefers in keeping some amazing reef tanks for nearly 30 years.

Whilst the attraction of a coral is generally based on the stunning colouration displayed by the fleshy polyp, that polyp can not exist without a healthy skeletal structure on which to grow.


Calcium carbonate skeletons are made up of three main macro elements, (Calcium, Carbonates ‘KH’, and Magnesium) as well as many other micro elements, such as Strontium, Potassium, Boron and many more. (We won’t go into too much detail regarding the specifics of the micro elements in this article but be aware that these elements are also required in the correct ratios for healthy skeletal growth.)

In-store we would describe corals as being a complicated multi-cellular organism, and as such the euphemism we use is that they require a full meal to grow healthily. Corals are unable to grow sufficiently from the scraps, as perhaps coralline algae might. Think of it as a Sunday dinner, with meat, veg plus carbs like say potatoes (in place of Calcium, Carbonates and Magnesium), and then the seasoning, salt and pepper, (as the micro elements). Corals are fussy, if the plate has no veg or potatoes, it isn’t going to eat the meat. Just as they aren’t going to grow if the carbonates or calcium levels are too low. The three elements must be there in sufficient ratios to one another for the coral to take them in and combine them into calcium carbonate. If one of these three elements is lacking, the coral simply won’t grow, or may grow brittle, inadequate skeletal structure leading to problems later.

Similarly, as corals may grow from these main ingredients, they may not like the meal as much without the salt and pepper (Micro-elements) and may also grow insufficiently and suffer longer term deficiencies leading to sub-optimal growth and brittle or inadequate skeletal structure.

These micro elements also contribute greatly to the overall colour and quality of the coral flesh, so it is important to choose a quality and comprehensive dosing mixture, which contains these micro elements too.



“Should I dose my tank to grow my corals?”

The short answer to this is, yes.

If you want corals to grow steadily, and healthily, then dosing is the simplest way to achieve this. Physically adding the elements your corals need to grow, is a variable which you can control. Simply waiting for your corals to find what they need out of the salt mixture is more like leaving it to chance. While you may test for the main macro elements, it is unlikely that you are testing for all the micro-elements and so you are assuming they are there and are available to your coral.


Most Common Misconceptions:

# My tank is mostly soft corals, so I don’t need to dose alkalinity, calcium and magnesium.

Soft corals may not form hard coral skeletons in the way which we would imagine them. Instead, they form calcium carbonate spicules on which the flesh of the coral is supported. The easiest way to describe this is as a web of fibreglass like spicules within the flesh of the coral. The key point here though is that these are, ‘Calcium Carbonate’, spicules, implying that they require calcium carbonate to grow. Attained by absorbing calcium, carbonates and magnesium from the water column, plus micro-elements, corals combine these elements to form calcium carbonate spicules, just as a hard coral would to build a skeleton. Therefore, it is still a good idea to dose the elements to your tank, even if you mainly stock soft corals.


# My parameters are constant and not going down, so I don’t want to dose and increase my parameters.

Simply put, if your parameters are not decreasing, then your corals are not using the elements in your tank, and they are not growing!

Your corals may have increased the fleshy portion of the polyps, especially in soft corals and LPS Corals, and these may expand and contract iterating an appearance of growth, but the coral skeleton isn’t growing, and neither are the spicules, therefore your coral isn’t really growing.

When we discuss dosing in the manner which we are today, the goal is not to increase parameters within the tank, but merely to provide the direct quantities of elements required by our corals to grow. The parameter levels should remain consistent, due to dosing the correct quantities of solution, as the corals use whatever we put in. If parameters start to rise, reduce the quantities you are dosing, and conversely if the parameters start to decrease, you should increase the quantities you are dosing.


# I water change regularly, so I don’t need to dose.

It is true that water changing with a quality salt will replace elements in the tank, and that your corals should grow somewhat following a water change. The trend we found from water changing alone is that you may get a couple of days of growth in between water changes. This would mean a couple of days per week if you water change weekly, or a couple of days per month if you water change less often. But the Ocean is so vast and self-sufficient, that these parameters do not really dilute, and therefore corals in the wild are exposed to these parameters constantly and are readily able to grow 24/7. This is the consistency we are trying to replicate in the tank by dosing. When dosing, the purpose of water changing is relegated to nutrient export only, while the dosing regime will maintain our coral growth elements.


Another important consideration for coral growth in reef aquariums is pH.

To understand the importance of pH in coral skeleton calcification and growth, we first need to understand a bit about the coral’s biology. Coral is a sessile invertebrate that belongs to the class Anthazoa. It consists of polyps, which are small tubular structures with tentacles surrounding the central mouth. Each polyp secretes a calcium carbonate skeleton. Calcification of the coral skeleton is a complex process that involves the uptake of inorganic carbon by the polyp, which reacts with calcium to form calcium carbonate. The pH of the water plays a vital role in this process, as it affects the concentration of carbonate and bicarbonate ions in the water. These ions are necessary for the chemical reaction to occur.

When the pH of the water is too low, the concentration of hydrogen ions in the water are high. This causes the concentration of carbonate ions to decrease, making it more difficult for the coral to extract sufficient carbonate ions to build its skeleton. When the pH is too high, the concentration of bicarbonate ions decreases, and this also hinders the calcification process because the coral needs both carbonate and bicarbonate ions to build its skeleton.

The ideal pH range for coral skeleton calcification and growth is 7.8 – 8.5 with most literature stating that a target of 8.2 to 8.3 is optimal. Many hobbyists and professionals are providing anecdotal evidence which suggests a pH in the higher limits of around 8.4 – 8.5 initiates an accelerated rate of calcification and here at aquatech we maintain a stable pH of around 8.43 – 8.48 in our reef and with similar results.

In a closed aquarium inside your home in the UK a higher pH can be difficult to achieve with many hobbyists’ pH sitting at the lower end of the tolerances, around 7.8 – 8.2.

This is mainly due to excess CO2 around the aquarium which is drawn in through protein skimmers in closed cabinets. This is especially prevalent in the winter months here in the UK when windows are predominantly closed, and air circulation isn’t great, and this can be exacerbated by the use of open fires and log burners or even gas fires and heaters.

Products such as co2 scrubbers for protein skimmers have gained in popularity for this reason and have proven to be quite effective. Another method is the dosing of kalkwasser, but I don’t tend to recommend this to beginners as there is potential to cause disaster with the slightest mistake or overdose.

Instead, our preferred option is to use our favourite dosing product, ‘Reef Zlements pH plus’.

Reef Zlements pH Plus

Reef Zlements pH plus is a 2-part dosing formula, which is easy to dose and competitively priced. It contains all of the necessary macro and micro elements required by your corals for calcification whilst simultaneously buffering the pH up. We have achieved our higher pH levels through dosing this product alone and we highly recommend it. The products are made in the UK, under laboratory conditions, and are very consistent. The product can be hand dosed or dosed using an automatic dosing pump such as the H2Ocean 4 Channel Dosing pump.

We prefer automatic dosing because this ensures slow and steady, regular dosing in precise quantities which maintain the most stability.


Okay, so I should dose my reef tank, where do I start?

The first stage before dosing your reef tank is to ensure a healthy base level of macro nutrients. Here at Aquatech we aim for a KH of around 9dkH, Ca of around 450ppm and Mg of around 1350ppm. We also require a pH between 7.8 and 8.5 and aim for the higher of these tolerances if possible.

The main concern here is the KH. Natural seawater found in coral rich seas has an average KH of around 7. So 7dkH would be the minimum we should allow our KH to fall to. However, the KH in the vast seas does not really variate from this and so this stability ensures the parameter stays safe for corals.

In cases of oceanic acidification, this KH is known to drop as carbonates bond to excess hydrogen, and this process contributes to coral bleaching.

Our aquariums do not possess the vast volumes of water which the seas do and therefore they are far less stable. This means that acidification is far more common in an aquarium, exacerbated by the release of carbonic acids as a by-product of filtration.

We aim for a higher KH value in our aquarium, to provide a safety buffer which combats acidification, and ensures that our levels do not drop too low and cause coral bleaching.

Alternately, having a KH level which is too high, usually around 12-13+ dkH, can result in something called precipitation. Precipitation is where the carbonates bond to calcium and form calcium carbonate independently in the water, creating the “snowglobe effect”, and crashing KH levels quickly and dangerously.

Many hobbyists have had great success in inducing faster coral growth by increasing KH to these higher levels, but we would not recommend this method for beginners, and this option is best reserved for the most advanced hobbyists, due to the risk involved.

9dKH is a safer option which allows for a tolerance of a few dKH either way before disaster strikes and is optimally sufficient for slow but steady coral growth in the aquarium. Steady consistency is the key to a luscious and healthy coral rich aquarium.

Calcium has a strict affinity to bind to carbonates and form calcium carbonate. Without delving too deeply into the science, magnesium plays an important role in interfering with this process preventing precipitation.

The average levels of calcium in coral seas are 400 – 420ppm. By aiming for a level of 450ppm in our aquarium we once again create a tolerance buffer to ensure our levels do not drop below this level of natural seawater. The distinct relationship between Calcium and Magnesium requires a ratio of 3:1, Magnesium to Calcium. This is the ratio required to maintain sufficient interference, by magnesium, of calcium’s affinity for carbonates, thus preventing precipitation.

If we want our calcium to be 450ppm, then we also want our magnesium to be 1350ppm, (3:1).

These base levels of macro elements can be commonly achieved with a quality salt mixture. We use H2Ocean Reef Salt at a salinity of 35ppt. Occasionally the parameters in the salt do not quite equate to the correct levels. For example, if the KH value is too low, then we can add a specific product such as, ‘Reef Zelements KH Buffer’, or, ‘Seachem Carbonates’, to increase KH up to 9dKH as needed. It is important to do this slowly to minimise shock to any existing corals or invertebrates. We can repeat this process for calcium and magnesium by using products such as, ‘Seachem Reef Complete’, for calcium, or, ‘Seachem Reef Advantage’, Magnesium.

Once the base parameters are correct, we can then seek to dose a quality two- or three-part dosing mix to offer the complete range of elements for our corals to grow.

The idea is that we never allow our base levels to drop below that guideline parameter range and we feed our coral growth using the dosing mixture to provide them with everything they need to grow healthily. When the dosing is correct, we shouldn’t see any changes in our parameters, even though we are dosing, because the corals are absorbing the dosing mix as we add it and combining it to form calcium carbonate skeleton or spicules.


Now that you understand the fundamental principles of dosing, lets discuss the method and get started.

To start, we recommend beginning slowly and testing. For the first week or two, you can dose half of the recommended dose from the product, and test and observe over time. It is important to test regularly, we recommend daily or every two days to begin with and log your test results for analysis later.

You should concentrate primarily on the KH and dose all ancillary products based on the KH Consumption. As you begin to dose you should start to notice some variance in your KH Levels, and surprisingly, it is common for your parameters to decrease when you first start dosing. This is because your corals have suddenly been presented with the correct ratios of elements to grow, and they may suddenly grow faster, depleting some of the existing elements. This is a good thing and means your corals have grown! You should simply increase your dose until the parameters become stable again through multiple tests. If your parameters have dropped below the initial base levels, you can use the other products to raise them back to the required level, in addition to the increased dosing.

Each of the products we recommend require equal dosing quantities of each solution in the two- or three-part mixture. Each solution should be dosed at least one hour apart to prevent instant precipitation by allowing the products to disperse thoroughly throughout the tank before mixing. This could be one solution in the morning and one at night if hand dosing a two-part mix, or each solution dosed equally every 2 or 3 hours, with each solution dosed one hour apart if automatically dosing the two or three-part mix respectively.

If for example, your sweet spot or consumption rate was 30ml per day, that would be 3.75ml or 4ml of each solution dosed 8 times per day/24-hour period at three-hour intervals one hour apart.

Essentially you can keep on increasing your dosing quantity, slowly, and repeating the process as necessary, until you find your parameters increase slightly from dosing.

At this stage you should reduce your dose slightly until eventually you find your tank's sweet spot, where parameters remain constant, even though you are continuing to dose daily.

It is important to understand that the recommended doses on the bottle are a guideline only and that each tank is individual in its exact consumption rate, so there is some experimenting required to find your sweet spot.

It is entirely possible that your tank may need far more than the initial recommended dose, and equally possible it may require far less. The important thing is that we find the right amount for your corals to consume and to grow, without changing parameters over time.

Once you find that sweet spot, and are confident with it, you can reduce testing somewhat.


Okay great! I have found my sweetspot, I have been dosing for a while and my corals are growing nicely, but now my parameters have started to drop lower?

As you can imagine, your reef tank is a dynamic environment and as your corals grow, the consumption rate will increase, since larger corals will consume more elements. You may also add more new corals to your reef, further increasing demand, and only testing will provide an accurate way to tell if this is the case.

Perhaps weekly testing for newer tanks, and monthly testing for more mature and stable tanks will be the most beneficial to ensure you don’t become complacent in assuming your levels are correct.

As your demand for elements increases, you should slowly increase your dosing to match your new consumption rate as required.


Okay, so that’s calcification… What else should I dose to ensure my corals have everything they need to be healthy.


One, often overlooked, requirement in the proper care of corals is protein.

Corals are not plants, they are animals, living in symbiosis with an algae (zooxanthellae) which trades nutrient for energy, in the form of carbohydrates. This energy is acquired through photosynthesis by zooxanthellae, in return for a structure within which to reside, (coral tissue).

Dosing amino acids offers significant benefits to the coral, by providing proteins, the building blocks for proper cellular function, as required by all animals.

Amino acids play a crucial role in coral health, growth, and coloration and adding amino acids to the tank water can provide numerous benefits for all corals.

Here are some of the main benefits of dosing amino acids for corals in a marine aquarium.


  1. Promotes Coral Growth

Dosing amino acids promotes the growth of corals by providing them with the essential building blocks needed to grow and thrive. Amino acids are the building blocks of proteins that the coral uses to build its skeleton and tissues. By dosing amino acids, the coral has the resources necessary to grow more quickly, which leads to larger, more robust corals.


  1. Enhances Coloration

Amino acids play an essential role in the formation of pigments within coral tissues. Adding amino acids to the water can provide the coral with the necessary amino acids, which can, in turn, enhance coloration. SPS corals, for instance, can benefit from brighter and more vibrant colouring from the dosing of amino acids.


  1. Supports Immune System

Amino acids are involved in the synthesis of antioxidants and nitrogen oxide, which help to regulate the immune response and keep the coral healthy. The immune system of corals is essential to their survival, and amino acid supplementation can help boost immunity and improve overall health.


  1. Stress Management

Coral is subjected to various environmental stresses, including temperature changes, light, and pH fluctuations, which can affect their health and contribute to coral bleaching. Dosing amino acids can help the coral handle such external stresses better. As the amino acid levels increase, the coral is better equipped to manage environmental stressors and reduce the likelihood of coral bleaching.


  1. Promotes Photosynthesis

Amino acids play a critical role in the functioning of the Zooxanthellae. Zooxanthellae are tiny algae that live within the coral tissues and are essential for the coral's survival. They provide the coral with many of their nutrients through photosynthesis. Dosing amino acids aids the zooxanthellae in their photosynthetic activity and the provision of energy to the coral.


  1. Increase Natural Defences

When a coral is healthy and well-nourished, it can defend against diseases and other unwanted invaders. By providing a consistent dosing regimen of amino acids, coral can maintain and increase its natural defences against unwanted bacteria and other pathogens, which may reduce or eliminate the risk of coral ailments.


In conclusion, dosing amino acids is a vital component of coral care in a marine aquarium. By providing corals with the necessary building blocks, you can promote growth, enhance coloration, support the immune system, help the coral manage stress, support photosynthesis, and increase natural defence mechanisms.

We recommend starting dosing slowly, at around half of the manufacturer recommended dose and slowly increasing this dose. Remember, the recommended doses are a guideline only, and dosing amino acids at the correct amount and frequency is essential; otherwise, excess nutrients may cause other aquarium issues.

Since excess protein leads to excess nitrogen, we found one way to hit that sweet spot for dosing volume is to slowly increase the dose until an increase in nitrate is present.

You can then reduce the dose slightly until nitrate levels are stable once again just as we described for dosing the macro elements earlier in this article. Testing frequently whilst increasing the dose is the safest way to achieve this and you must already have a good understanding of your tank’s nitrogen input and output since you need to be able to attribute the nitrate increases only to the dosing of amino acids. If your tank is newer or less stable, then there may be other factors influencing nitrogen levels and, in this case, you are better sticking to the recommended dose until your tank is stable.

We prefer to dose amino acids automatically throughout the day and night, and ’Reef Zelements Amino Plus’, has proven to be the perfect supplement for this as it does not need to be mixed or refrigerated prior to dosing.

 reef zlements amino plus is the perfect solution ensuring amino acid protein supplementation in reef aquariums

If you want to check out the products we use to dose our aquariums, then follow the links below


Reef Zlements - Z-pH Plus 2 PART Dosing Solution - Aquatech Aquariums

Z-pH Plus 2 PART Dosing Solution - Aquatech Aquariums

Z-Amino Plus - Aquatech Aquariums

Z-Amino Plus - Aquatech Aquariums

H2Ocean 4 Channel WiFi Dosing Pump - PRO - Aquatech Aquariums

H2Ocean 4 Channel WiFi Dosing Pump - PRO - Aquatech Aquariums

Hopefully after reading this, you understand the key principles of dosing your reef aquarium. An understanding as to why it is a good idea to dose, why we set the parameters we aim for, and how to effectively chase those numbers safely and ensure a long and healthy life for your corals. Let us know what you think by commenting below or emailing us.

If you have any further questions on dosing or the products we stock, to help your reef, please come and see us in store and we will be happy to discuss these with you.


Have a great day and carry-on reefing 😊 Sincerely, Tom. Aquatech.

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