Review: Onyx LED light by Rapid LED


The new dimmable Onyx by Rapid LED offers a mix of 14 CREE XT-E Royal Blue, eight CREE XP-G White, one CREE XP-E Green, four Semi-LED Violet UV and one Oslon 660nm Red LEDs, writes Chris Green. The lenses are 100 degrees for the red and green, and you can opt from a choice of 40, 60, 80 or 100 degrees for the others.

Coming in at a 90w power consumption, that works out at roughly 3w per light (plus power for the fan), and with a 3m/10' power cord, you should have no problem with plug access.

The unit itself is compact and weighs around 1.7kg, which is somewhat of a relief because you only get the option to suspend the light with the supplied hanging kit, as there is no bracket to mount it on the tank (this may be due to UK legislation). The hanging kit wires extend to about 2m/6' and are long enough to reach most ceilings I would have thought.

The DC controller for manual dimming has three separate light channels: blue, white and red/green/UV ranging from 0-10v — 1v being 10%, 2v being 20% and so on, with 10v being 100% intensity. Without the controller, the light will operate at full power. You can buy other analogue controllers but at considerable cost.

Tweaking the colours can be somewhat taxing and annoying, especially when you find your preferred setting only for something to knock the dial on the controller. It took me two weeks to find a colour-mix that my corals and I were happy with.

The unit has a single fan, which although not silent, is not deafening either and similar in noise level to a PC fan. With this, is a nifty heat sink that is easy to maintain and keep clean.

The company recommends that one unit will be ample enough for a 61cm/2' cube and you can link other Onyx to each other with the correct cables to cover larger tanks and areas with three being recommended for a 2m/6' tank.

It’s claimed that this light will be powerful enough for SPS and LPS coral growth and I tested it on a 94 l/21 gal River Reef that was supplied with 2x 36w PCT and the difference that could be seen compared to the supplied T5 PCT was astounding.

Fish, coral and rock colours stood out more and the fish seemed bolder under the new lighting, despite the increase in brightness and intensity.

The blues really are intense and you get a very good spread of light with good depth penetration as well.

Of course, you also get that lovely glitter and glimmer that is expected of LED lighting these days.

All my soft corals seem to love this light, and, based on the parameters this light has, I feel confident that it would cope relatively well with most light demanding corals.

The first major downside is that the cables from the dimmable controller to the light unit are far too short, being just shy of 61cm/2'.

Coupled with the controller power cord being just over 2m/4', I feel it is far too short to be fully adaptable to most aquarists’ needs. It should be longer so that you can hide it away in the cabinet if needed or away from the tank and out of sight. Considering that the light unit itself has more than an adequate length of power cable, this disparity is slightly vexing.

The instructions consist of a sheet with half a dozen pictures that show you how to connect the hanging kit up and some basic FAQs about the use of the controller, and that is it. No tools are supplied, but you need an Allen key at the very least to secure the clamps on the hanging wires.

I also feel, if legislation would allow, that a bracket to mount the light over the tank would be beneficial, as not everyone can suspend a light from their ceiling, nor want the prospect of heavy-duty wires and cables on show.  

A manual dimmer is maybe a poor choice when other lights have not only digital control, but fully programmable and nature replicating options.


That said I absolutely love this light. It is tremendous value for the money and small enough for most nano aquaria. Despite the lack of detailed and informative instructions, it is easy to assemble and suspend. Sound-wise, the fan is quiet enough so it isn’t that noticeable.

It looks neat, tidy and good quality and is a fantastic product. The company gives an 18-month warranty on them and a five-year return and fix policy. I’m not sure how this would work for returning to the USA though.

If I upgrade to a larger tank in the near future, then I’ll consider running two or more of these in line rather than a bigger single light unit. I would like to see how this tests long-term and with light-demanding corals, and I look forward to really giving this light a good workout.

Price: £299 (non-dimmable), £349 (dimmable), and £24.99 (manual controller).

More info: Tel. 01623 616969 or email [email protected]

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