# Berlin Method > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Berlin_Method > Markdown URL: https://mediated.wiki/source/Berlin_Method.md > Source: https://en.wikipedia.org/wiki/Berlin_Method > Source revision: 1338846959 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) Saltwater aquarium filtration method The **Berlin Method** of biological [filtration](/source/Filtration) is a method for maintaining a clean and stable environment within a [saltwater aquarium](/source/Saltwater_aquarium), typically a [coral reef](/source/Coral_reef) system. This method relies on the use of ample [live rock](/source/Live_rock) (rock with live marine organisms and bacteria on or in it). The theory is that [aerobic](/source/Aerobic_organism) [bacteria](/source/Bacteria) covering the surface of the porous live rock and sand convert harmful [ammonia](/source/Ammonia) (from fish and invertebrate waste) into [nitrites](/source/Nitrites), then [nitrates](/source/Nitrates), which are much less harmful to the tank's inhabitants. Through the process of [diffusion](/source/Diffusion), the [nitrates](/source/Nitrates) move deep within the rock where they are converted by [anaerobic](/source/Anaerobic_organism) [bacteria](/source/Bacteria) to free [nitrogen](/source/Nitrogen) gas. Left over [nitrates](/source/Nitrates) are removed through regular partial water changes, or with algal filtration such as an [algae scrubber](/source/Algae_scrubber). As an added measure, a [protein skimmer](/source/Protein_skimmer) is used to remove some of the dissolved organic compounds before they break down into [ammonia](/source/Ammonia), although skimmers do not remove ammonia from fish urea. The typical [rule of thumb](/source/Rule_of_thumb) is to use from 1-2 lb (0.45 to 0.9 kg) of [live rock](/source/Live_rock) per gallon (US) (3.7 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](/source/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](/source/Fish), [invertebrates](/source/Invertebrates) and [corals](/source/Coral) 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](/source/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](/source/Calcium_reactor), kalkwasser (calcium water – calcium hydroxide mixed with pure water) or a balanced two-part solution. ## References 1. [http://www.fishchannel.com/fish-fun/fish-terms/fish-definitions/berlin-method.aspx](http://www.fishchannel.com/fish-fun/fish-terms/fish-definitions/berlin-method.aspx) 1. [http://saltaquarium.about.com/od/denitratorunits/fl/What-Is-A-Saltwater-Aquarium-Berlin-Filtration-System.htm](http://saltaquarium.about.com/od/denitratorunits/fl/What-Is-A-Saltwater-Aquarium-Berlin-Filtration-System.htm) [Archived](https://web.archive.org/web/20150923104218/http://saltaquarium.about.com/od/denitratorunits/fl/What-Is-A-Saltwater-Aquarium-Berlin-Filtration-System.htm) 2015-09-23 at the [Wayback Machine](/source/Wayback_Machine) 1. [http://www.aquarium-design.com/reeftheory.html](http://www.aquarium-design.com/reeftheory.html) v t e Aquariums and fishkeeping Aquarium types Freshwater Marine Public Reef Brackish-water Community Biotope Aquarium décor and equipment Airstone Algae scrubber Berlin Method Bog-wood / Driftwood Calcium reactor Deep sand bed Filter Fishcam Fish feeder Heater Lighting Live rock / Live sand Powerhead Protein skimmer Refugium Substrate Sump Fish terms / types Algae eater Bottom feeder Coldwater Dither Hardy Painted Tropical Fish food Brine shrimp Daphnia Feeder fish Feeder shrimp Infusoria Shrimp mix Tubifex tubifex Other concepts Aquarium fishery Aquascaping Artificial seawater Bath treatment Book of Vermilion Fish The Cichlid Room Companion Clean-up crew Disease in ornamental fish Macquarium Project Piaba Reef safe Spawning trigger Water conditioner People Takashi Amano Herbert R. Axelrod Leonhard Baldner Pierre Carbonnier Edward Edwards George Farmer Ian A. M. Fuller Philip Henry Gosse William T. Innes Gerald H. Jennings Sven O. Kullander William Alford Lloyd Paul Matte George S. Myers Julian Sprung Anna Thynne Charles Haskins Townsend Jeanne Villepreux-Power Robert Warington Magazines Aquarium Fish International Koi Practical Fishkeeping Reef Hobbyist Magazine Tropical Fish Hobbyist Companies Dennerle Drs. Foster & Smith Hikari Hagen Sera Tetra Wardley Zoo Med Laboratories Organizations Aquarium fish clubs Marine Aquarium Council North American Native Fishes Association Lists Aquarium diseases Aquarium fish by scientific name Freshwater aquarium fish / amphibians / invertebrates / plants / algae Marine aquarium fish / invertebrates / plants Brackish aquarium fish / invertebrates / plants --- Adapted from the Wikipedia article [Berlin Method](https://en.wikipedia.org/wiki/Berlin_Method) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Berlin_Method?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.