[oceanarium]

Originally Posted by sven.fischer.de

Hi,

I've build several LED lamps and have read very much about them and corals. Additional I'm electrician and can value data sheets.

Let me give you a very short summarize:

- LED is about 20-30 % more energy efficiant than T5.
- A good point to start is 0.6 Watt per liter, for SPS about 1 Watt per liter.
- Always use active cooling, as it extends efficany and escecially lifetime very much.
- it's necessary to place the lamp close to the water surface to reduce light loss, as the typical angle is 140°
- Every LED emit light in one direction, at the opposide the heat! So you just get light into the tank!
- Lifetime is about 20 to 50,000 hours. Good cooling and less power is the key to dramatically extend lifetime. For example: LED rated at 350 mA nominal, but 700 mA possible with max. 1000 mA -> lifetime difference can be between 50,000 h @ 350 mA down to 15,000 h @ 1000 mA
- just blue and white LEDs are not sufficiant to power zooxanthelle. Important is 430 nm, 460 nm, 500 nm, 660nm. So a mixture of UV, violett, royal blue, blue, cyan, deep red and cool white is necessary to complete the needs(!) AND visual quality. In gerneral white LEDs should be (power rated) 1/3.
- optics are only necessary for >40 cm water depth

It's a very complex topic and ther's a very big difference in LED quality and efficancy. You can't compare easily LEDs - the are like cars and have many different attributes.

A good starting point is the well known US manufacturer Cree - you can save much money with clay-boa.com for DIY.

Enjoy LED - they have to potential to get more than double efficiant in future and the get cheaper and cheaper - it's just the future for sure.

Enjoy LED.

Sven

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I also add a little in the 400-410nm.