Initial Lighting Setup

The photosynthetic zooxanthellae which coral depend on have adapted to the ocean depths, photosynthesizing best when there is blue light present. Studies have shown that Chlorophyll A has a lower spectrum peak at about 430nm and chlorophyll B has a lower spectrum peak at about 450nm.

I’m building lighting setup for a small SPS aquarium with the following goals:

Lighting Design Goals

• Low cost by utilizing commodity electronics components
• Emphasis on blue spectrum lighting
• Enough white lighting to be aesthetic to the human eye
• Low heat to avoid heating issues in the summer months

To meet these needs I am building a lighting fixture from scratch using components sourced from E-Bay, Aliexpress, and local electronics resellers. This isn’t my first LED project so I am leveraging past experience building high wattage COB led lights for indoor growing. I’ve sourced the following COB led components:

Selected Components

• 14x7x1.25 inch aluminum heat-sinks. I’m using two of these, suspended over the tank. I acquired them for only $10 CAD each from a Concept Aquariums in Calgary during a clearance sale.
• 2 x CREE XTE 10 LED 50W COB from HotRed LED: 4 royal blues and 6 cool whites. Two will be suspended over the tank as primary lights, emulating 10-14k metal halide. They are $15 CAD each.
• Meanwell LRS-350-36 power supply. I’m reusing this 36 volt power supply from a previous high powered COB led project. I acquired mine for $35 CAD shipped through E-Bay.
• 3 x 600W step-up buck converters from E-Bay. I’m using the units with adjustable voltage and amperage clamps. I already own these and have chosen them to reduce costs.
• 8 x 420nm UV 10W COB leds. These are going to be dialed way down initially due to the risk of UV damage.
• 8 x Royal Blue 10W COB leds. Royal blue leds typically output 450nm light. These will balance out the cool white LEDs in the cree cobs.

The 10k CREE 50W leds will be mounted in the center of each aluminum heat-sink, surrounded b royal blue and UV spectrum 10W cobs. 3 different channels of lighting will operate on a buck converter each, allowing for fine control of the 10k, royal blue and uv lights. Lighting control won’t be very ergonomic with this setup because it will involve using a multimeter to monitor the voltage and amperage of the buck converters during adjustments, to ensure I don’t go over the forward voltage and amperage specs of each light.

The cree COB pucks have already arrived so I built the fixture and suspended it over the tank. I dialed the LEDs down to 60W total power output (62.5V and 0.9 Amps). When complete the final cost of the project will be approximately $110 in newly sourced equipment and about $80 worth of equipment already on hand.