Setup path
Reef tank setup guide: ten stages, in order
From an empty room to your first corals. Each stage says what you need, the steps, a checklist, the common mistakes and where sources disagree, and ends with a test your tank must pass before you move on.
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How does the setup path work?
Work down the stages in order. The checklist on each page saves your ticks in this browser only, and the depth gauge fills as you go, so you can close the page and pick up where you left off. Nothing is sent to us.
What are the ten stages?
Stage 1: Plan a reef tank: size, budget and UK running costs
Decide the size, the style and where the tank will live before you buy anything. These three choices set your budget, your electricity bill and how forgiving the tank will be for years.
Stage 2: Reef tank equipment list by tank size
What you need on day one, what can wait until the first corals, and the safety kit people skip and then regret. Sized for a nano, a mid-sized tank and a large tank with a sump.
Stage 3: Place and leak test a reef tank before adding salt
A leak found with fresh water in an empty tank costs a towel. The same leak found with rock, sand and fish costs a weekend. Level the stand, run it with fresh water and test the failure cases on purpose.
Stage 4: RO/DI water and mixing reef salt for a new tank
Make clean water, mix it to a salinity you can measure and hold, and get the temperature steady. Everything later depends on these three numbers being right.
Stage 5: Live rock or dry rock, and sand or bare bottom
Rock is where most of the filtering bacteria live; sand is a home for burrowers and a trap for detritus. Choose with your eyes open about pests, phosphate and time.
Stage 6: How to cycle a reef tank, and how to prove it is done
Bottled bacteria labels promise a cycle in days. Some are right for some tanks. The only way to know is a test you can do at home: dose ammonia, wait 24 hours, and see where it went.
Stage 7: The reef tank ugly stage: diatoms, algae and clean-up crew
Brown dust, then green film, then hair algae: almost every new tank goes through it. It is the tank finding a balance, not a sign you did it wrong. The aim is to ride it out, not to fight it with bottles.
Stage 8: A reef tank quarantine plan you will actually follow
One sick fish can take out a whole tank, and a fish with white spot cannot be treated in a reef full of invertebrates. Set up your quarantine before you buy your first fish, while the main tank is still empty.
Stage 9: First fish for a reef tank: what to add and how fast
Add hardy, peaceful fish a few at a time, with a fortnight between each group, and let the bacteria catch up. Speed is the most common way to undo the patience of the cycle.
Stage 10: First corals for a reef tank: when and which
Start with hardy soft corals at low light, add LPS once the numbers hold steady, and leave SPS until the tank has months of stable tests behind it. A cycled tank is ready for fish, not yet for corals.
How long does it take to set up a reef tank?
About two to four months from filling the tank to the first corals, if the cycle is quick and you add fish slowly. Longer without bottled bacteria. The plan below is ours, built from the sources on each stage page.
| Weeks | What you do | Move on when |
|---|---|---|
| Before week 0 | Plan, buy kit, place and leak test | Stand level; fresh water test dry for 24 to 48 hours |
| 0 | RO/DI, mix salt, heat, rock and sand, flow | Salinity and temperature steady for 24 hours |
| 0 to 2 | Cycle with bacteria and ammonia (4 to 8 weeks without bacteria) | Ammonia 2 ppm to 0.25 ppm or less in 24 hours, twice |
| 2 to 3 | Water change if nitrate is high; light on a modest schedule; first snails | Ammonia and nitrite zero; diatoms are normal |
| 3 to 6 | First one or two quarantined hardy fish; feed lightly; weekly nitrate and phosphate | Readings steady for two weeks |
| 6 to 10 | First hardy soft corals at low light | Corals open; nutrients measurable |
| 10 to 16 | More fish in small groups, two weeks apart; weekly calcium, alkalinity and magnesium | You can measure alkalinity use |
| 16 to 26 | LPS; start dosing if water changes no longer hold alkalinity | Alkalinity steady within 0.5 dKH a day |
| 26 onwards | SPS only once alkalinity, calcium and magnesium have held for months | Stable weekly logs |
Why does each stage end with a test, not a date?
Because the dates in published advice do not agree, and your tank does not read them. A bottled bacteria label may promise a cycle in five days; a keeper with dry rock may wait eight weeks. Both can be right. The test at the end of each stage tells you which is true for your tank.
What comes after stage 10?
The first-year maintenance schedule covers the daily, weekly and monthly jobs, how often to test as the tank matures, and when to start dosing. When you get there, methods compared sets out the ways to keep alkalinity and calcium up, and targets by brand explains why the numbers differ.
Sources
- Charterhouse Aquatics, how to set up a marine aquarium step by step
- Charterhouse Aquatics, a beginner reef keeper’s shopping list
- BRS, 5 Minute Saltwater Aquarium Guide, episode 15: cycling
- BRS, fishless cycling with ammonium chloride and bottled bacteria (Dr Tim’s recipe)
- BRS, seven steps to adding saltwater fish
- Charterhouse Aquatics, what to test in a reef aquarium and how often
- Reef Builders, how to avoid beginner mistakes