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Saltwater Aquarium Guide Reef-keeping magazine
Reef aquarium with colourful corals and small fish under blue water

Saltwater & reef aquarium guides

Build a Healthier Saltwater Aquarium

Practical setup guides, equipment comparisons, marine fish care, and reef-keeping advice to help you make better decisions for your aquarium.

Start Your First Saltwater Tank Explore Equipment Guides

Start here

New to saltwater? Work through these four in order and you will avoid the most expensive beginner mistakes.

See the full beginner path
  1. Step 1

    Planning Your First Saltwater Tank

    Tank size, where it goes, what it costs to run and the order to do things in.

    Read the first-tank setup guide
  2. Step 2

    Choosing Aquarium Equipment

    Turn a tank size and budget into a list of the gear you actually need.

    Open the equipment planner
  3. Step 3

    Cycling Your Aquarium

    What the nitrogen cycle is, how long it takes and how to tell when it is done.

    Understand the nitrogen cycle
  4. Step 4

    Choosing Your First Marine Fish

    Hardy, peaceful species that suit a new tank, and the ones to leave for later.

    See beginner-friendly fish

Browse by category

Jump straight to the part of the hobby you are working on.

Equipment guides & reviews

Write-ups of the gear that does the heavy lifting on a reef tank: light, flow, filtration, top-off and testing.

All equipment reviews

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Latest articles

All articles

Comparison spotlight: three popular reef LEDs, and who each one suits

All three can grow coral. The practical differences are how much tank one unit covers, how you control it and what the full setup ends up including.

More comparisons
Light Best suited to Control Keep in mind Read more / buy
AI Prime 16HD Nano and small tanks, or one unit per section of a longer tank. App control built in. A single compact unit lights a limited area; larger tanks need several. Mounts are sold separately. Read our AI Prime 16HD write-up Check price on Amazon (affiliate link, opens in a new tab)
AI Hydra 32HD Medium tanks, or deeper tanks that need more output per fixture. App control built in. Costs more per fixture than a compact light. Mounts are sold separately. Read our AI Hydra 32HD write-up Check price on Amazon (affiliate link, opens in a new tab)
Kessil A360X Reef keepers who want the shimmer of a single dense light source. Scheduling needs a separate controller or Wi-Fi dongle. Budget for the controller and mounting arm on top of the light itself. Read our Kessil A360X write-up Check price on Amazon (affiliate link, opens in a new tab)

Coverage depends on mounting height and the corals you keep. Check the manufacturer’s coverage chart for your tank dimensions before buying.

As an Amazon Associate I earn from qualifying purchases. Links labelled “on Amazon” are affiliate links. How this works

Fish & coral guides

Choose animals that suit your tank, not just the ones that look good in the shop. Every guide puts tank size and welfare first.

All fish & invertebrate guides

Free planning tools

Calculators and planners that run in your browser. No account, and your data stays on your device.

All 12 tools

How this site works

  • Explanations, not just answers

    Guides aim to explain the reasoning behind each recommendation, so you can adapt it to your own tank instead of following a list.

    Read the editorial standards

  • Affiliate links are labelled

    Some links go to Amazon and earn a commission if you buy. They are marked, and they never decide what gets recommended.

    Read the affiliate disclosure

  • Animal welfare comes first

    Stocking advice starts from minimum tank size, temperament and long-term care, not from what looks good on day one.

    Start with the beginner path