Lamp Comparison

            Light is one of the crucial parameters critical to success with coral. Perhaps one of the largest electric expenses involved with keeping a reef tank is due to running lights. Light Emitting Diodes (LEDs) consume less energy than conventional lights and produce considerably less heat than Metal Halides.

            With my system I will be testing several different LED light systems and natural sunlight schemes in an effort to reduce my overall energy consumption. I used a light meter to test the light intensity at varying depths for four different lamps. I used a 175 watt Coralvue 14k mogul base metal halide that was approximately 6 months old. I then tested a 180 LED Cluster. Looking straight into these lamps is not advisable.

            I also wanted to try out some easy to use screw in type bulbs that were available. I figure if they worked they would be easy to use as a retro fit for extra moon light, spot light or refugium lighting.

Lamp A

175 w 14k Metal Halide Mogul Base

Approx. 6 Months old

Lamp B

http://www.theledlight.com/led-clusters.html

Cluster 180L4 180 LED Cluster - 4.0" x 9/16" - 880ma @12-13.5vdc

Light Bulb C

24 LED screw in bulb

E27-x24 Medium Base LED Bulb with Narrow Viewing Angle
SPECIFICATIONS

superbrightleds.com

http://www.superbrightleds.com/edison.html

Light Bulb D

50 LED screw in bulb

E27-W50 Medium Base LED Bulb
SPECIFICATIONS

superbrightleds.com

http://www.superbrightleds.com/edison.html

Graphic Descriptions: The number in blue is the reading from the light meter. The top number was measured 1cm from the bulb/glass surface. Then 9 inches from the surface of the bulb and then again 9 inches under the surface of the water.

More Graphic Descriptions: This chart shows the light spread at 9 inches below the surface of the water. The red shows the diameter of the light spread.

Notes:

The beam from the 180 LED cluster was quite tight and maintained strong illumination in the center and at a distance. However outside this tight beam light dropped off dramatically. This effect was also noted with the smaller LED cluster bulbs but with much less overall intensity.

The light meter I used under reports blues and over reports some reds. With white lights this usually balances out and you get an accurate reading. However since the blue LED only produced blue we can assume the reading for that bulb is a little lower than what is actually produced.

The LED angle I used were rather tight, however there are LEDs with a wider angle. These might give you a spread more typical of a metal halide.

 3/8/06

LED Light Trials

 Applied Sustainable Aquaculture