Work out your own upfront, monthly and first-year costs →
What a reef tank costs to set up
| Size of setup | Equipment | Likely electricity in year one | Best for |
|---|---|---|---|
| Compact 50–70L all-in-one | £650–£1,050 | Roughly £100–£230 | A small footprint and a controlled starting spend |
| 100–150L all-in-one or sump | £1,100–£2,500 | Roughly £180–£420 | More water and more freedom to choose equipment |
| 300–500L system | £3,000–£7,000+ | Roughly £450–£1,000+ | More space and livestock, and a bigger ongoing commitment |
The electricity figures are examples, not forecasts. How often your heater runs and the real draw of dimmed lights and adjustable pumps make a big difference. Work out your own figure in the electricity calculator.
Where the money goes
The headline purchase, though what’s included varies hugely.
Return pump, wavemakers, filter media and an optional skimmer.
RODI unit, containers, refractometer and test kits.
Rock, sand, salt and your first round of consumables.
Three ways budgets go wrong
- Comparing box prices. One tank includes a light and return pump; another expects you to buy both.
- Forgetting the support kit. Mixing containers, a spare heater, extension leads and power protection, cleaning tools and plumbing parts all add up.
- Ignoring running costs. Electricity, salt, replacement filters, test reagents and failed parts keep coming after day one.
A better way to budget
Decide between an all-in-one or a sump, compare today’s starter tanks, work through the equipment checklist, then replace each allowance in the cost planner with a real price from your basket.
How we handle electricity
Our cost planner asks for the unit rate on your bill rather than assuming a tariff. Ofgem publishes price-cap rates by region and payment method, which are a useful reference but won’t match every household’s tariff. The separate electricity calculator starts with an editable example rate. We don’t assign any of your standing charge to the tank.
THE SHORT ANSWER
Budget for a working first year, not an empty tank
A realistic UK reef budget covers the tank and cabinet, lighting, heating, return pump and display flow, water preparation, rock and sand, test kits, salt, maintenance tools, getting ready for livestock and some contingency. The total can be far higher than the advertised tank price, especially if the package has no light, or if compact equipment needs replacing soon after you start.
Work with three numbers: the equipment you need to fill the tank safely, the equipment you need before the first livestock goes in, and the total cost of your first twelve months. That last figure should include electricity, salt, test reagents, filters, food and planned replacements. A smaller, complete setup beats a bigger one you can’t afford to run.
STEP BY STEP
How to do it
- 01
Pick a reference setup
Decide on the volume, all-in-one or sump, the corals you want, and whether the package includes a cabinet, light and return pump. A budget without a specific setup in mind is just a shopping list.
- 02
Price everything it depends on
Add water production, mixing, calibration, testing, electrical safety, mounts and adapters. Use current UK checkout prices, and include delivery for heavy items.
- 03
Estimate what you’ll use
Work out electricity from real wattages and schedules, salt from the litres you’ll change, and filter and reagent replacements from a cautious estimate of how often you’ll need them.
- 04
Add contingency and pause points
Keep money aside for missing fittings, a failed part or a fix you didn’t plan. Hold off on decorative and automation upgrades until the core setup is stable.
YOUR SITUATION
What to do in your situation
The complete build costs more than you can safely spend
Go smaller or start later. Don’t cut water preparation, testing or safety equipment.
Important equipment is missing or not up to the job
Compare the complete package total with buying the parts yourself.
Electricity, salt and consumables would stretch the household budget
Change the size, the equipment or your maintenance plan before you buy.
COMMON MISTAKES
Mistakes to avoid
Forgetting delivery
Big tanks, rock, salt and water containers can add a lot in shipping and handling.
Only pricing the first month
Reagents, resin, salt, food and electricity keep coming, and decide whether you can keep the tank going.
Treating future upgrades as optional
A weak light, return pump or chamber may need replacing. Include likely upgrades when you first compare options.
WORKED EXAMPLE
Turning a £700 tank into an honest budget
A £700 all-in-one includes the glass, cabinet, return pump and a basic light. The buyer then adds a heater, wavemaker, RODI unit, mixing container and pump, refractometer, test kits, rock, sand, salt, cleaning tools, protected extension leads and some contingency. The cost to reach first water is well above £700, before any livestock.
Looking at the full twelve months adds electricity, water changes, test refills, filter media and food. If that total feels uncomfortable, dropping the calibration fluid or test kits is a false economy. A smaller complete tank, or saving for longer, is the safer choice.
BEFORE YOU CHANGE ANYTHING
Write down where you’re starting from
Note the date, the equipment or product you’re using, how you measured and the conditions behind every important number. Say whether a volume is the tank’s label figure or your real net water; whether a flow is the box rating or what actually comes out; and, for test results, the salinity, test kit and time of day. A precise-looking number is useless once you’ve forgotten where it came from.
Change one thing at a time, and decide in advance what improvement will look like: a steady test trend, less detritus, a more stable temperature, a quieter tank or a lower running cost. One reading, or one good day, isn’t a trend, and a setting copied from someone else’s tank isn’t proof it suits yours. The free Reef Companion keeps your tests, maintenance and changes in one dated log, so you can see cause and effect.
MAKING CHANGES SAFELY
Protect your tank while you make the change
Take a baseline
Measure before you install equipment, change your chemistry or alter your routine. Take photos if placement matters, and note how your livestock behaves. Without a starting point, you can’t be sure what caused any difference later.
Start small
Begin with a cautious setting or dose, and keep a way back. Hang on to the old equipment until the new one has proved itself, keep your previous schedule, and don’t add livestock at the same time as a big lighting, flow or chemistry change.
Give it the right amount of time
Mechanical problems show up straight away; nutrient and coral responses can take days or weeks. Judge the change over a sensible period, but stop immediately if you see animals in distress, a leak, overheating or an electrical risk.
Afterwards, note the result and decide whether to keep, adjust or undo the change. If the result is unclear, go back to your last stable setup and measure better, rather than piling on another change.
SIX MONTHS ON
Check it’s still the right decision
What made sense on day one can stop working as livestock grows, the room warms up, equipment gets dirty or a routine turns out to be unrealistic. Set a reminder to review it in six months, comparing what you assumed with the reality: water volume, electricity, consumables, noise, cleaning time and test trends.
Test trends, real flow, temperature, light coverage or whatever the change was for
Is it still doing its job, with room to spare?
How often you clean it, how hard it is to reach, calibration drift and missed tasks
Can you keep this up without cutting corners?
Electricity, reagents, filters, spare parts, warranty and downtime
Would you make the same choice knowing the real cost?
If it’s working, you don’t need to replace it; the review simply gives you a reason to keep it, tune it or plan an upgrade before something fails.
KNOW THE LIMITS
When to get expert help
Get product-specific or professional help for anything involving floor loading, household electrics, unsafe plumbing, damaged glass, unexplained livestock deaths, or chemistry you can’t measure reliably. Use a qualified electrician for fixed wiring, and always follow the current safety instructions for your tank, equipment and additives. Never work around damaged cables, swollen batteries, leaking seals or equipment that keeps tripping the electrics.
Your livestock’s needs can also outweigh general equipment advice. Check adult size, behaviour, disease risk and each species’ light, flow and feeding needs with reputable care guides before you buy. This guide explains the equipment decision; it can’t guarantee the result for every animal or tank.
COMMON QUESTIONS
Frequently asked questions
How much does a reef tank cost in the UK?
It varies hugely with size and what’s included. Build an itemised budget with current prices rather than relying on an average.
Is second-hand equipment cheaper?
It can be, but allow for missing parts, worn pumps, outdated lights and not knowing the history of the glass and seals.
How much contingency should I keep?
Enough to fix an essential gap without debt or delay. How much depends on the size of the build and your household budget.