Arcadia OT2 LED lighting review


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In a PFK exclusive, Jeremy Gay reveals that the long wait is over. Arcadia's new hi-tech luminaire has finally arrived...

First given a teaser of what Arcadia were planning at the German trade show Interzoo in 2008, we have long anticipated this hybrid luminaire which incorporates both high power LEDs and linear T5 lighting.

It’s good…

With both LED and T5 this should cater for almost everyone. Blending the low energy, shimmer effect of LED with the widespread colourful T5, both types of lighting have their groups of fans and both could be used independently to grow corals.

Combine both in one unit and you have pleased both factions! The LED sceptics will get to experiment with LED while able to fall back on the tried and tested T5. You also benefit from uniform colour and shimmer.

In true Arcadia style the units look great, slick, slimline and silver.

A wider version of the OT2 luminaire, a middle section has been fitted, housing panels of LEDs, and the outer sections that normally contain four T5s in the OT2 — two each side — now contain three in each side, totalling six.

They can be ceiling suspended with length and height-adjustable fittings, or used in conjunction with the Series 4 support legs supplied separately.

I asked if the units would come with the same hinged and length adjustable legs as in the OT2, but Arcadia said that, due to the extra width and weight of these larger units, this would be unlikely.

Apart from LED and T5 working in combination in an attractive unit, other major features include several control possibilities. The LED panels comprise both cool white 8,500K and deep blue 450nm which can be dimmed and controlled separately on two channels. The six T5 tubes can also be dimmed and controlled in two separate channels in a bank of two tubes and four tubes.

Combined they offer complete control of four separate lighting channels, each dimmable from 0-100% over whichever timescale you wish. No matter what type of display lighting you prefer, by graduating the four channels, and having the option of fitting different coloured tubes, you should find the light blend for your tastes.

The connections box — not yet PFK tested — is said to allow the owner to hook up the unit to a computer, or even a household dimming system. It is also claimed to allow greater control and aid fault-finding to test the luminaire and manually set intensities of blue and white LEDs.

What’s more, the dimming controller can be set to create sunrise and sunset patterns, moonlight effects that mimic the lunar cycle and even cloud cover. Turn the T5s down, say Arcadia, and save money too as they will then use less electricity.

All these features have set the gadget fanatic in me on to maximum buzz!

We already have good wavemaking technology, so combine all these extra effects and it begins to get really exciting. I even have an actual rainmaker from a dart frog terrarium, so, in theory, I now get to play God and set cloud cover, kick in the rainmaker and then set my pumps to storm mode.

The prospect of lightning simulation was even discussed as not being impossible, by the guys at Arcadia. Oh the power!

Seriously though, we haven’t fully explored the potential of factors like lunar cycles in fish and coral spawning. Now the technology is here with which to begin experimenting.


All this technological wizardry comes at a price. I’m having several conversations a week with LED lighting companies exploring aquatics and all say that if you want the best you have to pay for them. There is no alternative.

Combine up to 56 LEDs in the largest 1,500mm model with six T5s, a nice looking unit and all those programmable features, and it doesn’t come cheap. Prices range from £900-1,950 with a typical 1,200mm, 40 LED unit going for £1,500, plus the controller which sells separately for £159.99.

At £1,660 a typical OT2 LED unit costs more than my car is worth and although it does a lot of things it won’t drive me to work! Top-end marine keepers are a wealthy bunch, though I do wonder about the price of this unit as, even discounted, it is way beyond the average reefkeeper.

Also look at the cost of ownership. The 1,200mm, 40 LED unit uses 420w of electricity with all four channels on full output.

A big plus point with LED is its green credentials, yet combine it with T5 and total power consumption in terms of those credentials flies out of the window. If you want to use that much power you could otherwise run ten 39w T5s, twin 150w metal halide plus tubes, 14 TMC AquaBeam 1000HD units or 35 AquaBeam 500s. 

"Reduce energy consumption by running T5 lights at a level appropriate to the size and depth of the tank," say Arcadia, yet if I paid £1,660 for a really bright light, would I then want to turn it down?

The physical width of the units is also an issue, as they really need to be suspended over tanks over 60cm/24” wide, front to back. On our 50cm/20” wide, 100cm/40” long test tank the outer T5 tubes are shining right down the front and rear glass, so you will need a wide tank to get the best from the wide T5 light spread.

Finally, I’m not thick but the controller has so many options and variables to set that I didn’t find it easy to programme. When the PC compatibility software comes out Arcadia assure me it will be more apparent and much easier, as run programmes and percentage dimming across the day will then be clearly displayed and easy to understand, and at a glance.

Vital statistics

Models and prices:

1,000mm six 39w T5 + 16 LEDs — £900

1,000mm six 39w T5 +32 LEDs — £1,200

1,200mm six 54w T5 + 24 LEDs — £1,150

1,200mm six 54w T5 + 40 LEDs — £1,500

1,500mm six 80w T5 + 32 LEDs — £1,400

1,500mm six 80w T5 + 56 LEDs — £1,950

Unit colour: Silver

LED panels: Each consists of eight LEDs; four blue, four white. All blue are fitted with 26° angled lenses. All white except one have 26° lenses, with one 8° lens for spotlighting. Panels are CREE XRE run at 700mA and have 50,000 hours operating life. White LEDs are 8,500K and blue 450nm.

The verdict

Arcadia have again demonstrated they are worthy of their respected place in the aquarium lighting market and although the technology of lighting is changing quickly they can still mix innovation with great design. With all the options in this package the unit should be future-proof.

I have concerns about the price tag which will keep these units beyond the reach of many who would crave them. A quick Internet search revealed LED units of up to £5,000 from some manufacturers, so you have to put everything into context — but, as with plasma screen televisions, will prices fall as technology becomes cheaper?

It’s a great gadget, though I am saddened that more hobbyists won’t get to own one. If your means are more modest take the less expensive and greener LED-only products from TMC.

Product: Arcadia OT2 LED

Price: From £900 - £1,950, not including the required controller at £159.99

Reviewer: Jeremy Gay

Rating: 4/5


  • Sleek, slimline, looks good.
  • T5 and LED in combination offers best of both worlds.
  • Advanced programming.
  • Dimmable T5 and LED.


  • Expensive.
  • Although slimline, units are wide and require 60cm/24” wide tanks.
  • The controller has so many variable options that programming can be quite a task. A forthcoming PC display should simplify matters.

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