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Discussion Starter · #1 · (Edited)
Hey there guys, i'm absolutely brand new to this forum and planted tanks, and aquariums in general!!

Over the next week I will be collecting the last few pieces needed to start my very first aquarium! ever!

Now, my dad manufactures LED lighting and I have an abundance of LED strips & power supplies, I am planning on mounting the LED strips onto a board that will sit over the center of the tank, similar to commercial LED lights for tanks available.

I am running a 12V power supply with 5A output, the maximum output of this unit in watts, would be 60w, I won't have any trouble mounting 60watts worth of LED strips above the tank.

The tank is a standard 2ft tank, 60cm X 30cm X 38cm and only about 68 litres (20 gallons)

After a little bit of reading it seems watts per litre isn't accurate,

So my question is, would 60watts of LED's that are between 6000K-7000K be okay for a 70litre tank that is 38cm deep (15inches)

Hopefully I have given enough info for an answer!
Don't mind the voltmeter, just the light :p


Thank you,
Kind regards
Just
 

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I believe these strips get fairly hot, so maybe aluminum housing would be better for heat dissipation as opposed to wood for mounting the strips on?
Sorry,can't guesstimate whether the light would be too much, but doubt it would be too little.
 

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Just throw in a $3 direct from China dimmer and not worry about "too much" light..
There are fancier option controller/timers..

 

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Since you are in a perfect situation for making your own LED light I suggest using a mix of LED colors, so you can adjust the lighting to make it look like you want it to. Keep in mind that plants can use some red light along with the typical blue dominated light from LEDs. And, I found that an aluminum bar or channel extrusion works great as a mounting/heatsink for this type of light fixture. You certainly won't be able to run your LEDs at 60 watts of power, without converting your tank into an algae farm, but the dimmer Jeffkrol recommended would allow you to run them at a lower, much more appropriate power. If you buy a $20 digital luxmeter from Ebay or other web store, you can use it to set the brightness of the light. Just prop the light the same distance from the floor as it will be from your substrate, use the luxmeter to measure the brightness, and divide the lux measurement by 70 for a crude measurement of PAR. A good PAR reading to start with is 40 (2800 lux, approximately).
 

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Discussion Starter · #5 ·
Thanks a heap for these awesome replies!!!

Right now my goal is to get this tank running with as little cost as possible, I am watching every single dollar.
The 2ft tank i'm using was second hand and cost me $10, I have everything I need to make the LED light except the aluminum channel, all hardscaping I have collected and cleaned,
I will need to purchase substrate, a filter, plants & fish.

Definitely working on mounting these strips onto some alloy as per your suggestion, also I have now obtained a dimmer which I plan to use again as per suggestion,

However in regards to colour, I only have a few colours, cool white, green & yellow, should I try and obtain some red? or would plain white do the job?
What other colour temps would you suggest?

Also to list a few, I would like to aim for some hair grass, anubias, java ferns & crypts, still undecided but along these lines.

Thanks again,
Regards
Just
 

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Green and yellow won't help the plants much - green can help the look of the light (in small doses). Plants want to see blue and red, around 450 nm and 660 nm. Cool white usually has quite a bit of blue in it already, but you will probably want to add either warm white or red to get more output in the reds. Half cool white and half warm white (2700K or so) is usually a good balance for plants and providing a nice look, but since you already have a lot of 7000Ks, it may be cheapest for you to add some 660 nm reds and call it done. That being said, all 7000K will still grow plants.

60 watts of LEDs for that tank will probably be a lot more light than you want. Not sure of the quality or efficacy of the LEDs you are using, but I am running about 85 watts of Luxeon LEDs over a 48 gallon tank and get about 130 PAR at the substrate at full blast. For the plants you are proposing you will want to stay around 30-40 par at the substrate, so I would guess you will be running your 60 watts of LEDs at 30% or less - much more than that and you will want to start thinking about adding CO2.

-Justin
 

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Green and yellow won't help the plants much - green can help the look of the light (in small doses). Plants want to see blue and red, around 450 nm and 660 nm. Cool white usually has quite a bit of blue in it already
Plants "see" and use the entire range of the visible light spectrum, as well as down into UV (and up into far reds, but that isn't pertinent underwater), with green light being as efficient as blue light for energy capture for photosynthesis, as well as helpful for deep-tissue CO2 fixation. Remember that plants are using far more pigments than the ChlA and ChlB you see on those charts. So you want a full spectrum and not simply blues and reds, regardless of the color rendition issue those would cause.

All whites have quite a bit of blue in them, including warm whites, since there's no such thing as a white LED. Agreed though--adding warm whites is a great way to subtly increase reds in the spectrum.
 
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