About Seafan

Sources and how we check our reef advice

Seafan is written from published sources, read and weighed one by one. This page explains where our advice comes from, how we decide between sources that disagree, and how to tell us when we get something wrong.

This page was last checked 21 October 2026. How we check

How do we mark each fact?

Every fact on Seafan comes from a source we name, with the date we read it. We also say how we read it, because a number seen in a search summary is weaker than one read on the page itself.

Read in full

We opened and read the page on the date shown. Numbers from these pages are shown as they are, with the source.

Typical, check

We saw the figure only in a search summary. We show it as a typical value to check, or leave it out.

Our reading

Our own inference from the sources, labelled as ours. Where we recommend something, we say why.

How do we weigh sources?

Not every source is equal. We read widely and give more weight to sources with less to sell and more to check.

Strongest

Peer-reviewed studies and government pages: for example the US CDC report on palytoxin, the PLoS ONE study of zoanthid toxins and GOV.UK guidance on CITES. We lean on these for safety and law.

Useful, with a known angle

Brand manuals and programmes (Red Sea, Triton, Tropic Marin, Seachem, Fritz) are clear about their own method but sell the products they describe. We give their figures and say whose they are.

Practical, often US based

Retailer guides and videos (Bulk Reef Supply, LiveAquaria, UK shops) are the deepest practical library. Many use US gallons and US products, and some contradict themselves; we convert units and point out contradictions.

Weakest on their own

Forums and single keepers show what goes wrong in real tanks. We use them to find problems and disagreements, never as the only source for a number.

What do we do when sources disagree?

When sources disagree we do not pick one silently. Pages have a "where sources disagree" table: the positions, who holds them, and our reading of why they differ (different methods, salts, coral types or test kits). Where it matters we give a safe band for beginners and the reasoning behind it.

Is Seafan independent?

Yes. Seafan learns from BRS TV, Red Sea, Triton, Tropic Marin, Reef Builders, Practical Fishkeeping, UK shops and many keepers, and is not affiliated with any of them. We write in our own words, quote rarely and briefly, and link to the original pages. We never copy text, tables or images from a brand, shop or forum. There are no adverts, sponsored pages or affiliate links, and no brand has seen or approved our pages.

Which units do we use?

Litres first, with UK and US gallons on request (1 US gallon is 3.785 litres; 1 UK gallon is 4.546 litres). Temperatures in degrees Celsius, salinity in ppt and specific gravity, alkalinity in dKH with meq/L.

Where do the photos come from?

Species photos come from Wikimedia Commons under Creative Commons or public domain terms (CC0, CC BY and CC BY-SA). Each photo shows the photographer and the licence under it, as the licences require. We resize them for the web and change nothing else. We never use photos from brands, shops or forums.

The full list of photos, photographers and licences is in the photo credits file. Where we found no clearly licensed photo, the page says so instead of showing one.

How do I report a mistake?

Spotted a mistake or an out-of-date figure? Email products@cameronshields.co.uk with the page address, what you think is wrong and a source if you have one. We read every report, correct the page and change its "last checked" date.

Email a correction