Methods
The Berlin method for reef tanks, explained
The oldest and plainest way to run a reef: rock does the biological filtering, a protein skimmer takes out waste before it breaks down, and regular water changes top up everything else. Most first tanks run on it, whether they call it that or not.
Last checked . How we check
- Cost
- Medium
- Effort
- Low to medium
- Suits
- Most beginners and mixed reefs
- Needs
- Plenty of rock, a skimmer, weekly water changes
How does it work?
Bacteria living in porous rock turn ammonia into nitrate. The skimmer removes proteins and fine waste before they rot. Water changes dilute nitrate and phosphate and put back calcium, alkalinity, magnesium and trace elements. There is no bio-media in the filter.
No one owns the method, so it publishes no targets. Keepers use general ranges such as those on our targets by brand page.
When does the Berlin method stop being enough?
Water changes put back only what the salt mix contains. Once stony corals grow quickly, alkalinity and calcium fall faster than a 10% weekly change can replace, and you add a dosing method on top. Reef Builders suggests measuring that fall with daily tests for a week before choosing.
How do I get started?
- Plan enough rock for the volume and an open aquascape.
- Fit a skimmer rated for the tank, or a little above.
- Change about 10% of the water every week with the same salt.
- Test alkalinity weekly; when it falls between changes, add a dosing method.
What are the common mistakes?
- Skipping water changes because the tank looks fine.
- Switching salt brands often, which moves alkalinity each change.
- Adding bio-balls or sponges that trap waste.
Where do sources disagree?
| Topic | What sources say | Our reading |
|---|---|---|
| Is a skimmer essential? |
| Essential on larger tanks; optional on lightly stocked nanos. |
Sources
Figures from sources read as a search summary only are shown as typical figures: check them before you rely on them. Found a mistake? Tell us how to fix it.