By the Aquarium Insider UK Team · Updated May 2026 · Independent, reader-supported

Best Rimless Aquariums for Planted Tanks UK: Sleek, Low-Iron Tanks for Aquascaping

Rimless aquariums have become the go-to choice for serious aquascapers in the UK. Unlike framed tanks with visible borders, rimless designs showcase your hardscape and plants without visual clutter—and they're genuinely easier to maintain. The open top also simplifies water changes, planting, and equipment access. But not all rimless tanks are created equal. Glass thickness, clarity, low-iron glass options, and CO2 compatibility vary significantly, and your choice depends on tank size, budget, and how demanding your aquascaping plans are.

What Makes a Good Rimless Tank for Aquascaping

The fundamentals matter. A quality rimless tank needs structural rigidity—cheap glass will bow under water pressure, which is both ugly and risky. Glass clarity is the second critical factor. Standard glass has a slight green tint due to iron content; low-iron (or "ultra-clear") glass is colourless and shows off your scape far better, though it costs more.

CO2 compatibility is worth considering upfront. A fitted glass lid helps retain CO2, which is why many aquascapers add one later. Some tanks come with lids included; others don't. The top edge profile also matters—bevelled edges are more refined and less likely to catch on nets or cause cuts during maintenance.

ADA Aqua La Mina and UK Clones

ADA's tanks remain the benchmark, though importing them directly to the UK can be expensive and slow. However, several manufacturers now produce functionally identical "ADA clones" that are readily available through UK retailers.

These tanks typically feature 5mm borosilicate or quality soda-lime glass, square or rectangular footprints starting around 45cm, and bevelled top edges. They're designed to scale beautifully—the proportions just work for aquascaping. Many use low-iron glass, which makes a real visual difference in planted tanks where you want green plants to look green, not tinted.

The main trade-off with clone tanks is that they're pricier than generic rimless options. Expect to pay £150–£400 depending on size. But if you're planning a display scape you'll keep for years, the glass quality and aesthetic refinement justify the cost.

Aquael Opti Set Range

Aquael's Opti Set tanks bridge the gap between budget and premium. You'll find them stocked at most major UK aquarium retailers, which means genuine UK warranty support and easier returns. The 60L and 90L sizes are particularly popular for planted tanks.

These tanks come with decent quality borosilicate glass and a fitted glass lid—a real advantage if you're planning CO2 injection. The lids aren't sealed, so they still allow for traditional maintenance, but they do help stabilise temperature and gas exchange. Glass clarity is solid, though you won't get the absolute transparency of low-iron options. Most Aquael tanks use standard glass rather than ultra-clear variants.

The Opti Set advantage is value. A 90L Opti Set typically costs £80–£150, making it accessible if you're starting out. They're sturdy enough for high-tech planted setups and reliable. The main downside is that the aesthetic refinement isn't quite on par with ADA-style clones—the proportions feel slightly boxy and the edges lack that premium feel.

UNS Tanks—Premium Glass and Precision

UNS (Ultra Nuvo System) tanks offer a different approach: high-end borosilicate glass with superior clarity, often available in low-iron variants. Their rimless designs are clean and minimalist, with excellent glass thickness and precise manufacturing. UK retailers now stock the main UNS sizes, particularly the 90P (45cm) and 120P (60cm).

These are genuinely premium tanks. Glass quality is exceptional—the clarity rivals anything on the market. UNS also designs their tanks with CO2 in mind, so the top edge is refined and there are subtle features that support long-term planted setups.

The catch is price. UNS tanks start around £250 for entry sizes and climb steeply. If budget is tight, they're hard to justify over the Aquael or ADA clones. But if you're planning a display tank and want the absolute best in glass clarity and build quality, they deliver.

Low-Iron Glass: Worth the Investment?

Low-iron glass removes the green tint, making plants appear more vibrant and reds look genuinely red rather than dull. It's genuinely noticeable and worth the premium if you're showcasing high-colour plants like Ludwigia repens or Alternanthera reineckii.

However, it's not essential for green plants or heavily scaped tanks where hardscape dominates. Standard glass is perfectly functional and saves money. Many successful aquascapers use standard glass and simply work with the colour palette it provides.

Sizing and CO2 Practicality

For UK planted tanks, the 45cm (60–90L) and 60cm (120–180L) sizes strike the best balance. They're large enough for meaningful scaping, small enough to maintain without difficulty. Both sizes integrate CO2 readily and heat efficiently.

Very small tanks (under 30L) struggle with stability—temperature, fertiliser, and bioload fluctuate too quickly. Larger tanks (over 250L) are stunning but heavy (often 300kg+ when filled), require dedicated stand space, and demand more equipment investment.

Making Your Choice

Buy a rimless tank based on your genuine aquascaping ambitions, not aspiration. If you're experimenting with hardscape and moderate planting, an Aquael Opti Set is sensible. If you've kept planted tanks before and know you'll maintain a high-tech setup, the ADA clones or UNS offer better long-term satisfaction. Skip low-iron glass unless you're absolutely certain you'll appreciate the difference.

Check compatibility with your planned hardscape and equipment—some tanks have slightly deeper dimensions than others, which affects how tall your layout can be. And verify that UK retailers stock replacement components if needed; local availability matters more than a marginally cheaper import.

Good rimless tanks last a decade or more. Buy once based on how you actually keep tanks, not how you hope to in future.