Leds And Plant Growth

[Biulu]

I am looking for a lighting system over my 20 gallon long and am interested in LEDs. However, I am hearing contradictory information with regards to plant growth.

What should I be looking at if I were to choose a LED lighting system in a planted tank?

 

[SuperColey1]

If I were doing a 20 long then on the old flouros T8s I would be looking at in the region of 30-40W, 2 to 4" above the water surface . With LED I would be dropping that down to 20-30W and raising it up to be 6 - 12" inches above. If you are confident with DIY and can get the drivers and supplies would be ideal to use 20 x 1W (or 21 to make 3 rows of 7) If using 3W then probably 2 rows of 4. Depends on the LED though if it is a super dooper Cree then you can use a little less than using an outdated LED like the Luxeon.

It's mainly dependent on how you are going to 'package' them. If you are able to suspend the unit then you can add more W and have the flexibility to raise the unit up to achieve a little less. If you get something like the RapidLED PWM youy could have the flexibility to set times and push the levels up or down dependent on the current tanks requirements etc. Underpowering them slightly (dimming etc.)

LEDs are much more flexible than other forms of lighting. gives you much more options at the start in terms of wher you place them, numbers to use et al. Flouros and MH go up in pretty large increments meaning if a tank is 2ft you are moving up in15W increments when you add a tube. With LEDs you can move up in 1W increments, 3W increments etc.

Andy

 

[Biulu]

Thanks Andy! I have been hearing that if you want LEDs for plant growth that the 1 Watts are no good. That you need to have lights of at least 3 Watts each. From what you are telling me, it sounds like that is not true?

 

[SuperColey1]

It isn't true. No idea how people are giving out that spiel. Many of the top 'proven' brands are using 1W. Both that you link to are as well.

What won't work are the traditional LEDs. The ones that are quite literally a piece of coloured plastic with 2 wires poking out the end. The sort of LEDs you find in those silly flashing bikelights.

They are good for visibility but not illumination. People can see you because of the light but they won't light up the road I assume that these are what one of those luminaire is using alongside the 1W described as 0.06W. They are for effect only. The 1W are fine.

Only problem there is with 1W compared to 3W is more wiring, more drivers, more complicated to wire etc. Thats why I used 3W. 1W would have meant 45 LEDs to match the 15 x 3W and that would be a lot of soldering, a lot of drivers, more power sources etc. Better to leave that amount of wiring to an electrician. lol