Aquariums Ltd OptiWhite tanks


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Rimless OptiWhite glass aquariums are starting to make significant breakthroughs into the marine market. We sent Dan Crawford, founder of the UK Aquatic Plant Society, to Aquariums Ltd., in Lancashire to see one made.

Dan writes:

“People like me will be well aware of the rimless, braceless OptiWhite tanks made famous by planted aquascaping god Takashi Amano and a lot of emphasis is now placed on what’s actually in the tank as you would expect.

“However, many aquascapers take aesthetics as a whole to another level now and insist on minimal design for their tank, cabinet and lighting. Pendant-style lighting is generally suspended above the tank by wires, or there’s a luminaire fitted above the tank.

“The cabinet is generally minimalist, with few lines to detract from the aquascape.

These factors allow the aquascape to take centre stage, which is how it should be.

 “Another benefit of open-top tanks is the ability to view it from a different angle. This can still be achieved on an open-top tank with rims and braces, but the effect is ruined by large, obtrusive braces running across it. The rims or edging strips also affect above and front-on viewing.

“Eliminating these allows for viewing without distraction.

Is OptiWhite better?

“These tanks offer only one constructional benefit over a normal float glass aquarium — aesthetics. Having said that, almost every planted tank fan I’ve spoken to recently feels that for this benefit, it’s certainly worth paying a premium.

“So what makes it better? In essence, it’s clearer glass! Most enthusiasts will think ‘my glass is clear enough’ and this is of course true, but to truly appreciate OptiWhite‚ for the first time, then it’s best viewed next to a normal float glass aquarium. The difference is astonishing.  

“So how is it clearer? In short, less iron is used in the making of the glass. Iron gives glass its green coloration and this is particularly noticeable when you are looking straight down the edge of the aquarium’s glass.

“OptiWhite has less iron and is therefore less green. Minimal iron content creates more of a neutral blue colour and in certain light appears almost completely clear. The discrete use of clear silicone improves the sleek look of these tanks and again offers no distraction from what’s inside.

The challenge...

“While planted tank fans have been using these methods for a few years, these new ideas are slowly also making their way into marine fishkeeping.

“PFK challenged aquarium manufacturers Aquariums Ltd., to design and build a modern, functional reef tank which could work in harmony with and further enhance a range of marine equipment and practices also at the cutting edge of the hobby.

“Many talks ensued over issues with sumps, weirs and overflows, the tank was designed in principle and I was invited to visit and document its construction.

Crucial decisions

“When planning a custom-built tank, the first factor to consider is size. If wanting a rimless tank it can be no taller than 70cm/28” and a maximum of 180cm/71” long. Front to back it can be up to 90cm/36” wide, but as the size of the tank increases so does the thickness of the glass and price. If planning a large tank ask a professional builder if your floor will be suitable for such a weight.

“PFK opted for a 100 x 50 x 50cm/40 x 20 x 20” tank for their reef. The 50cm/20” width front to back being important for better aquascaping — especially with corals concerned.

 “Also decide if the tank is to be drilled. If so, ensure it’s drilled in the perfect place, as once holed, there’s no going back.

“Since, by design, rimless tanks have no hood to house lighting, alternatives need investigating and there are many alternatives and variables. Pendant-style lighting needs to be suspended above the tank and the most effective way is from the ceiling.

“Luminaires do a similar job and can be hung from the ceiling or mounted to the tank’s edges, This does, however, eliminate bird’s eye viewing and can detract from the tank’s contents.

Colour options

“The cabinet, if sticking with a modern theme and contents remaining the focal point, should blend in with the rest of the room as seamlessly as possible. Aquariums Ltd., have 59 options of cabinet finish and there’s a colour for every taste and combination of home furnishing.

“PFK requested this cabinet be made without handles to keep it as minimalistic as possible and the company’s response was to supply push-fit doors with magnetic catches to allow easy opening.

“Each cabinet is computer designed and then CNC routered to millimetre precision. All the cabinets are made from18-22mm/0.7-0.9” chipboard, sealed with a waterproofing varnish then machine laminated.

Getting it built

“The glass was cut to size and polished before I arrived, so it was a case of watching while the craftsman got to work. I observed that one piece of glass was thicker than the rest and asked why. It was the back panel and the one to be drilled, being 12mm, while the rest were due to be drilled 10mm.

“I was shown the process behind the drilling and we needed a 50mm/2” equidistant hole drilling for the pipe, starting 40mm/1.6” down from the tank, so a 50mm/2” diamond core drill bit was added to the pillar drill.

“This has a constant water feed to keep the bit lubricated and cool while the bit spins at a quite slow 250 rpm, but this created a perfect, almost polished hole.

“The glass was thoroughly cleaned and taken to a workbench for assembly. Each panel edge to be joined to another has tape applied to the joining edge, then 10 or 12mm is removed with a razor blade to reveal a clean glass edge for the silicone to be applied.

“Silicone is then applied to the glass and the first panel dropped into place. Many glass clamps and brackets were used, each with its own specific purpose.  

“The most important tools are the right-angle brackets which hold the two end panels in place and allow the front and back panels to be fitted. They ensure the tank is completely square. More brackets are added and the tank is left to set.

“Before the tank can be filled it has to be left to cure. As a general rule, it should be left for one day for every millimetre of thickness of glass, so this tank had to be left for 12 days before being put to the test.

“Every aquarium is tested once cured and this tank had no leaks, and was fit for an eagerly-awaited delivery to the PFK office.”

Building stage by stage

 Cabinets are CNC routered by computer.

Computer design allows mm precision.

Machine laminated in 59 finishes.

The pillar drill with 50mm diamond bit.

PFK requested a 50mm hole for pipework.

Glass panels are taped before joining. 

Clamps hold the glass in place, for curing.

The verdict

I’ve watched almost the whole process of construction and to see it in situ now brings a whole new dimension to the way I look at this tank. It is fantastic! Now it’s up to PFK to make what’s inside look as fantastic as the outside.

Rimless OptiWhite tanks are here to stay, and will become  ever more popular. Once you make the switch to the minimal but elegant look of an OptiWhite tank, you’ll never want to go back…

Product: Aquariums Ltd., OptiWhite aquarium

Price: The bespoke model we had built cost £230.41 for the tank and £206.86 for the cabinet. Non-OptiWhite glass models are also available.

Reviewer: Dan Crawford

Rating: 4/5

More info: Aquariums Ltd.,  0870 850 7029


  • Modern, bespoke design
  • Deal with the people who actually build the tank.
  • Clearer glass, better viewing.


  • OptiWhite is more expensive - but its worth it!
  • Fish may jump from open topped tanks.

This article was first published in the October 2009 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.