# Low tech LED lighting?



## k38 (Nov 9, 2014)

Hello,

I've had many tanks in my life, but none since I took down my long-running reef about 8 years or so ago. Decades ago I had a bunch of FW tanks, and was very successful with fish, but not nearly so much so with plants. In those days, lighting was restricted to incandescent or dim florescent bulbs. (I used very brilliant CF over my reef). 

Now I've got the itch to set up a tank again, and maybe try live plants. Lighting technology has left me far behind, so here's my question:

For a 20 long (or maybe a deeper 29), I'd like to know what the best LED fixture is for medium light plants. I don't want to get into the CO2 thing at this point. If anyone responds, I'll probably have some follow-up questions too!

Thanks in advance,
Bill


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## bdevillier19 (Mar 24, 2014)

while i'm still a noob to planted tanks as well, from what i have gathered, either the current usa satellite+ or the finnex planted+ will be a medium range light. one thing to note is your choice on a tank. the 29g is taller than the 20 long so the par at the substrate will be effected by the height of the tank, as well as the height at which the light is mounted above the water.


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## falcooo (Sep 30, 2011)

As stated above, distance between from plants to light will effect PAR values greatly. But the Planted+ would be a good option to provide medium light in the 20 long. I have one on my nano tank and so far I love it. I did not want to get into pressurized CO2 either, so I dose excel daily.


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## Django (Jun 13, 2012)

The drop-off of light from the source to the substrate is demonstrated by the Inverse-Square Law as pertains to light. Wikipedia has an article on the inverse-square law at http://en.wikipedia.org/wiki/Inverse-square_law#Light_and_other_electromagnetic_radiation








An excerpt: Light and other electromagnetic radiation

"The intensity (or illuminance or irradiance) of light or other linear waves radiating from a point source (energy per unit of area perpendicular to the source) is inversely proportional to the square of the distance from the source; so an object (of the same size) twice as far away, receives only one-quarter the energy (in the same time period).

More generally, the irradiance, i.e., the intensity (or power per unit area in the direction of propagation), of a spherical wavefront varies inversely with the square of the distance from the source (assuming there are no losses caused by absorption or scattering).

For example, the intensity of radiation from the Sun is 9126 watts per square meter at the distance of Mercury (0.387 AU); but only 1367 watts per square meter at the distance of Earth (1 AU)—an approximate threefold increase in distance results in an approximate ninefold decrease in intensity of radiation."


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## k38 (Nov 9, 2014)

Very interesting. Is there a fixture you would recommend for a) a 20 long; b) a 29?

Bill


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## knm<>< (Mar 18, 2010)

I use the ecoxotic e-series. You can dim it to reach your desired lighting level. Plus, you can go high light later if you choose.


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## Django (Jun 13, 2012)

The article mentions watts per square meter to express the source of light's intensity. To estimate lumens from watts for various types of lamp, see http://en.wikipedia.org/wiki/Luminous_efficacy#Lighting_efficiency

Excerpt:

"Lighting
See also: LED lamp and Incandescent light bulb

Lamps used for lighting are commonly labeled with their light output in lumens; in many jurisdictions this is required by law.

A 23 watt compact fluorescent lamp emits about 1,500–1,600 lm.[3][4]

On September 1, 2010, European Union legislation came into force mandating that lighting equipment must be labelled primarily in terms of lumens, instead of watts of electric power consumed.[5] This change is a result of the EU's Eco-design Directive for Energy-using Products (EuP).[6] For example, according to the European Union standard, an energy-efficient bulb that claims to be the equivalent of a 60 W tungsten bulb must have a minimum light output of 700–750 lumens.[7]
To estimate lumens from watts for various types of lamp, see luminous efficacy." http://en.wikipedia.org/wiki/Luminous_efficacy#Lighting_efficiency

"Lighting": http://en.wikipedia.org/wiki/Lumen_%28unit%29


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## Raymond S. (Dec 29, 2012)

My brain doesn't always work in math when reading instructions.
Just to make sure on this...If my tank has a light 12" up from the sub and I raise it by 6"
then I'm getting half as much light as I was before I raised it ?


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## Django (Jun 13, 2012)

Itensity = 1/distance squared

= 1/12"squared = 1/144"​
= 1/18"squared = 1/324​
144"/324" = 44.4% less light

Hope that helps - I can read math but I was always terrible in math :wink:


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## k38 (Nov 9, 2014)

knm<>< said:


> I use the ecoxotic e-series. You can dim it to reach your desired lighting level. Plus, you can go high light later if you choose.


Thanks! This is just the kind of info I'm looking for. 

Bill


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## TECKSPEED (Jan 2, 2013)

I use a planted plus+ over a standard 20 gallon and that throws me into the low to medium par Range. If i were you I would lean towards a fugeray for the 20 long you can always buy "more light" but never diminish it once you buy it you know. So the planted plus on the 29 should do you well and I'd say a fugeray on the 20 long will let you get away with no co2


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## k38 (Nov 9, 2014)

Much obliged, Teckspeed!

Bill


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## TECKSPEED (Jan 2, 2013)

No problem anytime


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## ForensicFish (May 19, 2013)

I have had good luck with the wave point LEDs. Look for the 6700k clamp light in 12".


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## Sparklescale (Nov 22, 2013)

Something to consider; with a 30" long tank, many of the standard light fixtures are actually 24" in a 30" housing. I have a 37g, 12x30x22" which has a 3" black support in its middle, so 24" lamps in the center of a 30" housing results in dim ends and a shadow in the middle...very inefficient use of lighting. At first I bought a Current planted +, but, it also is just a 24" light with extenders to fit a 30" tank...so all the light is centered again. Even without water in my tank, I felt it would not be enough light (although for a 20L it should be good). I was new to planted fw having come over from reefing, and, it just seemed too dim-without even using it, and of course, it was not long enough to light the ends. Anyway, I turned around and bought a 4x24w fluorescent fixture instead...which was also 4 24" lamps in a 30" casing...and also turned out to be too much light running the two double lamp fixtures for a low-tech 37, although I have adapted it by using a siesta mid-day and raising it up to 8-12" above the water level and dosing ferts and glut a couple times a week. Just some things to consider in your search. I know the 20l does not have the center brace...not sure of the 29, but, if it does, and you get an LED light with all the lights centered, you will lose out on much of the available lights. I want to re-do my lights on my 37g, and if and when I can afford to do so, I plan to go with a BML with a dimmer as their 30" fixture has a 3" gap in the center, instead of all the lights clustered in the center. HTH


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## k38 (Nov 9, 2014)

Thanks, worth thinking about.

Bill


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## NCSteve (Dec 17, 2012)

Regarding your 29...I recommend the finnex planted +. I had a satellite + on my 29 and it's just a 24" fixture stretched out to 30". I had dark sides and very low light at the substrate level. I bought a finnex for it about a month ago and am very happy with it. It's a full 30" fixture and much brighter than the satellite. 
My 29 is low tech dosing ferts twice a week and excel only. I'm growing swords, crypts, bacopa and a few stems on l aromatica that was all green on the satellite but is showing color already with the finnex. 

Sent from my HTC One M8


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## k38 (Nov 9, 2014)

NCSteve,

Is the Planted + the only light over your 29?

Regards,
Bill


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## NCSteve (Dec 17, 2012)

Yes that's all I have on it now. My 29 is not that wide (12" front to back) and the light spread is fine. 

Sent from my HTC One M8


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## heine19 (Sep 22, 2014)

I have a planted+ over my 29 and like it. If I had the money I would have sprung for the ecoxotic for better features but the light is good. I run 2x 2L of diy co2 and have HC spreading and most plants growing well.


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