The Bulb Product info says:
• Includes twelve 1 watt Cree LED emitters
• Optimum PAR 65K Daylight emitters
• 95 lumens per watt
• 8 inch x 8 inch light spread at 8-12 inches from aquarium
• Simple operations as it fits into a standard household E26/E27 incandescent socket
• The PAR 38 LED is 5 inches wide by 4 inches with a light spread of about 12-13 inches when light is mounted 8-10" above water surface
• Focused Lumen Output
So, now I wonder is I really only need 1 PAR38 bulb?
The tank is only 15 deep and will house low light plants. If I go this route I'll use a track light pendant to mount the light so height adjustment or even adding a 2nd pendant is a non issue.
Because of the coverage, I think you will need 2 eventually and you can adjust the height when needed. A sign of too much light is algae growth faster than your plants
A lot of my clients use the cord from Ikea that looks like this:
Flickr 上 WingoAgency
的 White E26-27 Light Bulb Extension IMG_1770
Pretty stylish when dangling from the ceiling.