Berlin Method
Encyclopedia
The Berlin Method of biological filtration
is a method for maintaining a clean and stable environment within a saltwater aquarium, typically a coral reef
system. This method relies on the use of ample live rock
(rock with live marine organisms and bacteria on or in it). The theory is that aerobic
bacteria
covering the surface of the porous live rock and sand convert harmful ammonia
(from fish and invertebrate waste) into nitrites, then nitrates, which are much less harmful to the tank's inhabitants. Through the process of diffusion
, the nitrates move deep within the rock where they are converted by anaerobic
bacteria
to free nitrogen
gas. Left over nitrates are removed through regular partial water changes. As an added measure, a protein skimmer
is used to remove some of the dissolved organic compounds before they break down into ammonia
.
The typical rule of thumb
is to use from 1-2 lb (.45 to .9 kg) of live rock
per gallon (US) (~ 4 liters) of aquarium water depending on the density of the rock – or filling the tank up 2/3 of the way to the top. The benefit of using live rock
is fourfold: First, live rock acts as a biological filter, adding beneficial bacteria. Secondly, it introduces an abundance of marine life into the aquarium that many fish
, invertebrates and corals use for food. Thirdly, it provides a natural reef appearance with ample places to locate corals. Lastly, live rock will also help balance and stabilize PH
in the aquarium.
Calcium, alkalinity and other trace elements which are consumed by corals, are replaced through water changes (using natural seawater or a quality synthetic salt mix) or the use of a calcium reactor
, kalkwasser (calcium water) or a balanced two-part solution.
Filtration
Filtration is commonly the mechanical or physical operation which is used for the separation of solids from fluids by interposing a medium through which only the fluid can pass...
is a method for maintaining a clean and stable environment within a saltwater aquarium, typically a coral reef
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
system. This method relies on the use of ample live rock
Live rock
Live rock is rock from the ocean that has been introduced into a saltwater aquarium. Along with live sand, it confers to the closed marine system multiple benefits desired by the saltwater aquarium hobbyist...
(rock with live marine organisms and bacteria on or in it). The theory is that aerobic
Aerobic organism
An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment.Faculitative anaerobes grow and survive in an oxygenated environment and so do aerotolerant anaerobes.-Glucose:...
bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
covering the surface of the porous live rock and sand convert harmful ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
(from fish and invertebrate waste) into nitrites, then nitrates, which are much less harmful to the tank's inhabitants. Through the process of diffusion
Diffusion
Molecular diffusion, often called simply diffusion, is the thermal motion of all particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size of the particles...
, the nitrates move deep within the rock where they are converted by anaerobic
Anaerobic organism
An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It could possibly react negatively and may even die if oxygen is present...
bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
to free nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
gas. Left over nitrates are removed through regular partial water changes. As an added measure, a protein skimmer
Protein skimmer
A protein skimmer or foam fractionator is a device used mostly in saltwater aquaria to remove organic compounds from the water before they break down into nitrogenous waste...
is used to remove some of the dissolved organic compounds before they break down into ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
.
The typical rule of thumb
Rule of thumb
A rule of thumb is a principle with broad application that is not intended to be strictly accurate or reliable for every situation. It is an easily learned and easily applied procedure for approximately calculating or recalling some value, or for making some determination...
is to use from 1-2 lb (.45 to .9 kg) of live rock
Live rock
Live rock is rock from the ocean that has been introduced into a saltwater aquarium. Along with live sand, it confers to the closed marine system multiple benefits desired by the saltwater aquarium hobbyist...
per gallon (US) (~ 4 liters) of aquarium water depending on the density of the rock – or filling the tank up 2/3 of the way to the top. The benefit of using live rock
Live rock
Live rock is rock from the ocean that has been introduced into a saltwater aquarium. Along with live sand, it confers to the closed marine system multiple benefits desired by the saltwater aquarium hobbyist...
is fourfold: First, live rock acts as a biological filter, adding beneficial bacteria. Secondly, it introduces an abundance of marine life into the aquarium that many fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
, invertebrates and corals use for food. Thirdly, it provides a natural reef appearance with ample places to locate corals. Lastly, live rock will also help balance and stabilize PH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
in the aquarium.
Calcium, alkalinity and other trace elements which are consumed by corals, are replaced through water changes (using natural seawater or a quality synthetic salt mix) or the use of a calcium reactor
Calcium reactor
In marine and reef aquariums, a calcium reactor is a device used to create a balance of alkalinity in the system. An acidic solution is produced by injecting carbon dioxide into a chamber with salt water and calcium rich media. The carbon dioxide lowers the pH by producing a solution high in...
, kalkwasser (calcium water) or a balanced two-part solution.