Berlin Method

Lore & Background

The Berlin Method centers on the use of live rock, which hosts aerobic bacteria on its surface that convert harmful ammonia from fish and invertebrate waste into nitrites, then nitrates. Through diffusion, nitrates move deep within the porous rock where anaerobic bacteria convert them to free nitrogen gas. Leftover nitrates are removed via regular partial water changes or algal filtration such as an algae scrubber. A protein skimmer is used as an added measure to remove dissolved organic compounds before they break down into ammonia, though it does not remove ammonia from fish urea.

Reader's Guide

The Berlin Method's significance lies in its reliance on natural biological processes to maintain water quality in saltwater reef aquariums. The use of live rock provides a fourfold benefit: it acts as a biological filter by adding beneficial bacteria; introduces marine life that serves as food for fish, invertebrates, and corals; offers a natural reef appearance with places to locate corals; and helps balance and stabilize pH. The typical rule of thumb is to use 1-2 lb (0.45 to 0.9 kg) of live rock per gallon (US) (3.7 liters) of aquarium water, depending on rock density, or fill the tank two-thirds full. Calcium, alkalinity, and other trace elements consumed by corals are replaced through water changes (using natural seawater or a quality synthetic salt mix) or via a calcium reactor, kalkwasser, or a balanced two-part solution. The method's legacy is as a foundational approach for reef aquarists seeking a self-regulating ecosystem.

Did You Know?

• The Berlin Method relies on aerobic bacteria on live rock surfaces to convert ammonia to nitrites, then nitrates.
• Anaerobic bacteria deep within live rock convert nitrates to free nitrogen gas through diffusion.
• A protein skimmer removes dissolved organic compounds before they break down into ammonia, but does not remove ammonia from fish urea.
• Live rock helps balance and stabilize pH in the aquarium.