What Nutrients does Marine Macro Algae need to grow?
Beside of sufficient light marine macro algae will just need a few major and minor nutrients to thrive in the marine aquarium well.
The amount they need will mainly vary with the
But as algae don't grow with roots, the nutrients must be supplied through the water and not through the substrate ( like Freshwater aquarium plants which can be fed by fertiliser through the substrate).
In a reef tank or marine aquarium setup with just a few
They will not thrive well in an environment without or very little Nitrate and Phosphate, or where additives are used as a Nitrate and Phosphate remover as these are the key nutrients macroalgae need to grow and survive.
Please find at the end of this overview our recommendations for what water values your aquarium should have to keep marine
Beside of the major nutrients Nitrate and Phosphate they will need some minor nutrients like Iron, Sulfate, Biotin, Manganese and Iodine, which will normally be added with your regular water changes or can be added with separate trace element additions.
If the marine aquarium has a lot of
The following list shows major and minor nutrients which macro algae will need to grow successfully in a marine aquarium.
Always be careful on what and how much nutrients you dose into your marine aquarium, as it might harm fishes, invertebrates or corals when used not correctly. We can not take any responsibility for this!
If you have any questions or if you would like to know more about this please contact us.
The main nutrients which are necessary for a good and healthy
Nitrate, Phosphate, Magnesium, Potassium, Calcium, Sulphur and Carbon.
Nitrate is the major nutrient which is necessary for the
In the marine aquarium Nitrate if normally enough available, due to the nitrogen cycle and the fish waste. In fact, often the nitrate levels in marine tanks are so high, that it leads aquarists to think about the use of
In a marine aquarium with soft coral and/or fishes, it is normally not a problem to have a Nitrate Level between 5-10 ppm.
Whilst reef tank owners with hard corals will aim for a much lower nitrate level so that it is just available in traces.
When your Nitrate Level is too low, which will be often just the case within heavily planted marine aquariums, like our main cultured macro algae tanks, you might need to add this nutrient to the water. We add regularly CaNO3 ( Calcium Nitrate ) to maintain a Nitrate Level of 5 ppm. Another way to add Nitrate would be KNO3(Potassium Nitrate).
Phosphorus is the second main nutrient for the
In the marine aquarium, this is often enough available in the form of Phosphate PO4. Phosphate will be mainly introduced into the marine aquarium with fish food like flakes and especially frozen food blocks, but as well through detritus and fish waste.
But even the often recommended Phosphate level around 0.03 ppm is enough for a marine aquarium with just a few macro algae in it.
This lower Phosphate level is recommended especially when hard corals are kept, as a higher level will negatively infect the coral growth.
Magnesium will be often sufficient enough available in the marine aquarium, as it will be replaced with saltwater changes.
In heavily planted marine tanks it might be necessary to add magnesium to maintain a Magnesium level around 1250-1350 ppm
Calcium is again another important element for the marine
Unfortunately, calcium can't be easily added to the marine aquarium like other nutrients/elements, as the available calcium in the marine water depends and influences directly with the Alkalinity and PH Level of the marine water.
There are readily mixed solutions available which will keep that balance intact by increasing the Calcium level.
We use Calcium reactors to maintain a good calcium level of around 430 ppm.
As mentioned before adding Calcium alone to the marine water will affect your PH and Alkalinity levels. For
Potassium is another important nutrient for
Sulphur is normally sufficient enough available as it will be replaced with water changes.
Last but not least macro algae will need carbon for its growth, which will be turned into oxygen. Carbon will be sufficient enough available in
Beside of the Major Nutrients, marine
Sometimes these nutrients are often referred to as trace elements.
As for Major Nutrients, it won't be necessary to add any of those Nutrients/Elements to a marine or reef aquarium with just a few macro algae in it. Just in heavily planted marine aquarium setups, it might be necessary to add some of them periodically.
We add to our algae tanks mainly the following minor nutrients:
Especially in heavily planted marine tanks, it might be necessary to add Iron. There are a few ready mixed Iron solutions available,
which are specially made for marine aquariums. Be careful with normal Iron Solutions, as they might include Nutrients/Elements, which can be harmful to the marine aquarium inhabitants.
There are ongoing discussions about what Iron level should be maintained. We have actually good experiences with an Iron level between 0.05-0,1 ppm.
Like with the supplement of Iron there are ongoing discussions about the benefits of adding Iodine to the water.
We actually add one drop per 100l every few days to our tanks and are happy with that. Especially Red and Brown Macro Algae species are believed to grow better with it. There is, unfortunately, no recommended Iodine level available.
Very rarely we add some Vitamin B12 to our tanks, and just in very low amounts, as we noticed
Other minor Nutrients are as well necessary for the growth of
macro algae, but they are normally sufficiently replaced by water changes.
Manganese, Copper, Molybdenum, Zinc and Boron
For a macro algae tank we recommend the following recommendation for the marine water chemistry:
This may be different for reef tanks or systems with a refugium ( sump )
As a general rule, this is for most macroalgae species we sell, but there will be some which will need a different environment.
If you are unsure please ask us before you order.
Temperature: Between 23-28 °C
Salinity: 1.024 - 1.025
Nitrate: Between 3-10 ppm
Phosphate: Below 1 ppm, good is 0,03 ppm
Magnesium: Around 1200 ppm - 1350 ppm
Calcium: Around 400 ppm - 450 ppm ( high levels are important for calcified species like Halimeda)
Iron: Around 0.01 ppm
Iodine: around 0.04 ppm