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QUICK VERDICT
Our picks at a glance
The Bubble Magus Curve 5 is the budget sump skimmer to beat, the Tunze 9004 is the answer if you have no sump, and the Nyos Quantum 120 is the compact premium choice.
Best budget sump skimmer
Bubble Magus Curve 5
£110–£125
Budget sump skimmer; listings quote anything from 300 to 700L, so don’t size it on the highest claim
Search Amazon UK ↗Best if you don’t have a sump
Tunze Comline 9004
£148–£170
The pick if you don’t have a sump; Tunze quotes 60–250L depending on load
Search Amazon UK ↗Best compact premium skimmer
Nyos Quantum 120
£300–£320
Compact premium sump skimmer; leave margin below its up-to-500L claim
Search Amazon UK ↗OUR PICKS IN DETAIL
Who each one is really for
Best budget sump skimmer
Bubble Magus Curve 5
Best for
Budget sump skimmer; listings quote anything from 300 to 700L, so don’t size it on the highest claim
Why we picked it
In-sump AC; 8W; 300l/h air listed.
The catch
185 × 180 × 470mm; 241–279mm water
Yes, but size it cautiously rather than going by the biggest litre figure you see advertised.
Search Amazon UK ↗Best if you don’t have a sump
Tunze Comline 9004
Best for
The pick if you don’t have a sump; Tunze quotes 60–250L depending on load
Why we picked it
In-display / rear section; 4W; 150l/h air.
The catch
110 × 90 × 305mm; 225–245mm immersion
Yes, for fitting in the display or rear chamber, once you’ve confirmed the water depth and cup access work.
Search Amazon UK ↗Best compact premium skimmer
Nyos Quantum 120
Best for
Compact premium sump skimmer; leave margin below its up-to-500L claim
Why we picked it
In-sump AC; 8W listed.
The catch
150 × 210 × 465mm; about 210mm water
Yes, if a compact, high-quality sump skimmer matters more to you than the lowest price.
Search Amazon UK ↗HOW WE RESEARCHED
How we chose
We compared manuals, manufacturer specifications, current UK retailer listings, running requirements, ownership costs and support. This is desk research, not hands-on testing, and where something is uncertain we say so.
- Realistic capacity, with margin
- Footprint and room to lift out the cup
- Water depth it needs
- Air draw and power
- Control, spare parts and UK support
The short answer
The Bubble Magus Curve 5 is the budget sump skimmer to beat. The Tunze 9004 is the answer if you don’t have a sump. The Nyos Quantum 120 is the compact premium choice. The Red Sea REEFER DC 300 makes most sense if you already use, or will pay for, its controller and the ReefBeat app. The Deltec 600i is the premium pick for easy servicing, but check which generation a shop is actually selling.
| Model / checked price | Type / size | Published performance | Our take |
|---|---|---|---|
| Bubble Magus Curve 5 £110–£125 | In-sump AC 185 × 180 × 470mm; 241–279mm water | 8W; 300l/h air listed | Budget sump skimmer; listings quote anything from 300 to 700L, so don’t size it on the highest claim |
| Tunze Comline 9004 £148–£170 | In-display / rear section 110 × 90 × 305mm; 225–245mm immersion | 4W; 150l/h air | The pick if you don’t have a sump; Tunze quotes 60–250L depending on load |
| Nyos Quantum 120 £300–£320 | In-sump AC 150 × 210 × 465mm; about 210mm water | 8W listed | Compact premium sump skimmer; leave margin below its up-to-500L claim |
| Red Sea REEFER DC 300 £349 skimmer; about £499 with controller bundle | In-sump DC + app controller Two footprint orientations; 530mm high; 160–200mm water | 20W; 500l/h air | Excellent control and overflow protection, but the controller adds to the real price |
| Deltec 600i / SC-Pro 600i £431–£473 | In-sump DC Check exact 600i generation before ordering | Adjustable 24V DC | Premium, easy to service, with overflow protection; retailers’ names and specs vary |
Why skimmer ratings mislead
The Curve 5 shows the problem: UK listings for the same basic model quote anything from 300–500 litres to 500–700 litres. Red Sea, by contrast, publishes separate ratings for SPS, mixed-reef and fish-only tanks. You can’t line these numbers up in one “capacity” column as if they meant the same thing.
Electricity is the smallest cost
Running around the clock at 26.11p/kWh, a 4W skimmer costs about £9 a year, 8W about £18 and 20W about £46. The purchase price, controller, replacement pump, how easy it is to clean, and the risk of having to buy twice usually matter far more. Try your own tariff in the electricity calculator.
Sources and limits
We checked specifications against Tunze and Red Sea, plus current UK distributor and retailer listings for Bubble Magus, Nyos and Deltec. Prices come from Complete Aquatics, Finest Aquatics, Porton Aquapet, Marine World Aquatics and Perfect Aquatics. We haven’t measured noise, air draw, skimmate production or long-term reliability ourselves.
WHICH ONE FITS YOU?
Match the type, the load and the space you have
A budget sump setup
The Bubble Magus Curve 5 is tempting on price, but its conflicting capacity claims mean you should size it cautiously. Check the water depth it needs and the cabinet clearance before calling it a bargain.
A tank with no sump
The Tunze Comline 9004 works where a sump skimmer can’t. It will be visible, though, and the depth it needs to sit at becomes part of your display design.
A premium, controlled system
Red Sea’s DC model or a Deltec makes sense when adjustable control, overflow protection and easy servicing solve real problems for you. Include the controller and the exact model generation when you compare prices.
HOW TO CHOOSE
What to check before you buy
Work out your real water volume
Add up the display, the sump and an allowance for rock and sand, rather than going by the tank’s name. Then leave a margin, instead of matching your tank to the maker’s biggest number.
Measure the space it needs
Measure the footprint in every orientation it can sit, the water depth, the total height and the room to lift out the cup. Cabinet braces and pipework can rule out an otherwise perfect fit.
Look at air and pump figures in context
Air intake and power are useful clues, but neither tells you how well it will perform on its own. Neck design, water flow, adjustability and your actual bioload all matter.
Keep the water level steady
A sump skimmer works more consistently in a chamber with a steady water level. A stand can fix the depth, and an auto top-off stops evaporation constantly changing it.
RUNNING COSTS
What it costs after you buy it
Pump and impeller spares
A skimmer often outlasts its pump. Check you can get impellers, pumps, seals and cup parts in the UK before letting a small saving decide for you.
Cleaning
Build-up in the neck changes how the foam behaves. Think about cup access, drain options, cleaning the air intake and how hard it is to get the pump out of the sump.
The controller
Some DC skimmers are listed without the controller you need for app features or linked safety functions. Compare the complete package, not just the skimmer body.
ALTERNATIVES
Other options worth a look
A smaller, cautiously sized model
A smaller skimmer can be easier to set up on a lightly stocked reef. Oversizing isn’t automatically safer if the skimmer can’t hold a steady foam head.
No skimmer
Some lightly stocked tanks manage with water changes, a refugium or filter media, but you’ll need to manage gas exchange and watch nutrient trends deliberately.
HOW WE RANK
What it takes to make our list
It has to fit
Before we compare features, we rule out anything that doesn’t suit the tank, the installation or the job. A famous name can’t win if its size, operating range, connections or controls make it a poor match.
Claims need context
A spec sheet tells you what a product is designed to do, not how it will behave in your reef. So we look at the conditions behind every capacity, flow, output and accuracy claim, and flag any conclusion that’s an informed judgement rather than a measurement.
Every pick shows its catch
Each product’s main drawback sits right next to its biggest strength. We don’t hide a support worry, a missing accessory, a vague rating or a pricey ecosystem just because the product is the best choice for one type of buyer.
UK ownership breaks ties
Availability, what’s actually in the box, consumables, spares, UK plugs and the warranty route all count. When two products do the job equally well, the one that’s easier to own in the UK gets the stronger recommendation.
We don’t publish a one-size-fits-all league table. Each award answers a different buying situation, and the final verdict explains which trade-off we’d make. If your tank, budget or routine doesn’t match any of them, use the checks above to build your own shortlist rather than just buying the top badge.
COMMON QUESTIONS
Frequently asked questions
Should I buy a skimmer rated for twice my tank size?
Not as a hard rule. Makers use different assumptions in their ratings, and heavily oversizing can make it hard to run steadily. Leave a sensible margin instead.
Why does the water depth matter for a skimmer?
Water depth changes the pump pressure and the balance of air and water inside. Stick to the stated range, in a chamber with a steady level, rather than constantly re-tuning around a changing sump.
Are DC skimmers better than AC ones?
DC skimmers can be adjusted and linked to safety features, but add electronics and cost. A well-sized AC skimmer can be better value if you don’t need fine control.
BEFORE YOU ORDER
Three checks before you pay
Confirm the exact model
Shop listings often mix up generations, sizes and regional versions. Check the full model code, UK plug, included accessories and who handles the warranty against the manufacturer’s own details. Save the product page and spec sheet in case the listing changes.
Price everything it needs
Add the mount, controller, adapters, consumables, test kit and likely replacement parts you’ll need to run it. Compare that first-year total, not the headline price, and keep a little extra for plumbing, cable tidying or the fitting you forgot.
Measure twice at home
Measure your tank, cabinet, sump chamber, glass, sockets and the space you need to service it. Then write down the one job this kit has to do, and how you’ll know it’s working. If it won’t fit, or you can’t tell whether it’s doing its job, it’s the wrong choice.
Prices and stock change quickly. Every price here is a dated UK snapshot, so confirm the total at checkout and the returns terms, and don’t swap in a similarly named model without running these checks again.
OUR VERDICT
The right skimmer fits twice
It has to fit your tank’s nutrient load and the physical space. The Curve 5 is the budget option to check, the Tunze 9004 is for tanks without a sump, the Nyos offers compact premium performance, and the Red Sea or Deltec belong on a shortlist when you’ve budgeted for premium.
Track your nitrate and phosphate in the free Reef Companion after installing it. The trend will tell you whether your skimmer, and the rest of your nutrient export, is doing its job.