Night lights for your fish

A common problem for fish is not being able to find the bathroom when the house is dark.  To solve this issue, various manufacturers market “Lunar LED Lights” for aquarium use.  I have purchased two separate makes of these, and have compared their lighting ability in my 54 gallon corner bow-front tank.  The two that I have are the Coralife Lunar Blue-Moon-Glow and the Current Nocturnal Blue, with an additional link light.  Both generate light with a 470nm wavelength, but the designs are fairly different.  The Coralife is a single LED, with a permanently attached cord/transformer.  If you want multiple lights, then you need to use multiple transformers.  The Current light has 2 LEDs per module, with detacheable cord/transformer, and the modules are designed to link.  I have two modules, and the modules are attached to each othre with a 2 foot long cord (included).  The Coralife fixture is supposed to be about 1 watt, and it’s power transformer is rated for 1.8 watts (4.5 volts, 400 mA).  The Current fixtures do not specify their wattage, but it’s transformer is only rated for 1.8 watts (6 volts, 300 mA), and that transformer is supposed to power 7 modules (or about 0.25 watts per module).  So, with 2 modules, I am only getting half a watt of light output.

Lets compare what the two look like.  I used a 3.2 second exposure on my Canon SD900 camera, set up on a tripod in a room that was dark except for the glowing of power lights and of course the LED lighting on the tank.  Fish are blurred because they wouldn’t sit still no matter how many times I asked them to.

First, let’s look at the Coralife.  It has a pretty good spread for a single light, and for the shape tank it was easy to work with, just laid it onto the glass canopy on top of the tank:

Coralife Lunar light on 54G bowfront

As you can see, it is a bit spot-lighty, because it is so bright.  It does a good job since the tank is tall, giving it the distance it needs to be able to completely light up the gravel.  For a long tank, you will need multiple lights.

Next up with have the Current lights, I have them spread out about 12 inches apart, both just laying on top of the canopy.

Current Lunar link lights on 54G

They are obviously much darker, having trouble lighting up the plants like the Coralife did.  But, at the same time they are less spot-lighty, since they are not as overwhelming.  You can still see on the water surface where they are placed, but it is not as over-the-top.  Maybe with one more light it would be the perfect amount of lighting, but then it becomes annoying running wires all over the canopy and laying out the lights for balanced coverage.

Finally, I took a picture with both the Coralife and the Current lights on at the same time.  This was not surprisingly very bright:

LED Lunar lights on 54G aquarium

Too much light for my taste (it really shows off the algae on the back sides of the tank), but might be good for a reef tank. I will stick with the Coralife for the light in this tank, and use the Current lights on my 30 gallon tank.  It’s 36″ length requires two lights, and the smaller output of the Current lights shouldn’t overwhelm the tank.  In simple tests with the Coralife on the 30G tank, it was way too bright, and didn’t cover half the tank evenly.  The Current lights also aren’t the most even light in that size tank, but since they are darker it isn’t as noticeable.  I suspect if I had a 55G or other larger-size long tank that 2 or 3 Coralife lights would do a nice job, and have the handy feature of mounting directly to the body of Coralife lighting fixtures (which I don’t have, so it isn’t very handy to me).

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