# How much light is TOO much light for el natural?



## ab420 (Feb 11, 2008)

I have a Coralife 24" 65 watt power compact light fixture sitting around, and want to use it for an el natural style aquarium. The tank will not get much sun light, if any...

The light will be mounted about 3" about the tank, but about 4" from the surface of the water.

I was originally thinking about a 10 gallon, but that's 6.5 watts per gallon... pretty high... I also have a 20 gallon high tank sitting around that I could use (after a LOT of cleaning lol). That adds some depth to the water, and cuts it down to around 3 1/4 watts per gallon. Is this still too much?

My goal, is to run no equipment at all (other than the light). 

I plan to have a LOT of plants growing, and VERY few fish... most likely a few cardinal tetras... so the bio load will be very low.

The room it will be in is always at a constant temperature, and the tank will stay around 72 - 75 degrees naturally. If it swings too much, I'll add a heater, but I highly doubt I will need it.

I do not want to run co2 on this tank... I have a 29 gallon planted tank with co2 and 130 watts of light over it, but this new tank I want to replicate nature as much as possible in a little glass box.


So... I need to know:

10 gallon : too small for 65 watts of powercompacts? (pretty sure I know the answer there!)

20 gallon high: still too small?

Thank you very much in advance!


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## mommyeireanne (Oct 24, 2007)

I believe you should aim for between 2-3 watts per gallon. Cool White or half Cool white and half 'grow' lights work best, but still between 2-3 watts per gallon total. I believe if you had some sunlight you'd go 2 watts or even a bit less, per gallon.... I'm not exactly sure about how sunlight works into this equation, maybe someone else will let us know, here... I have an hour or two through the front of sunlight on my 10 gallon NPT. And a good 12 hour photo period. Read Ms Walstad's book. It is invaluable. It would have saved me several mistakes (and some expense) if I'd read it first. Now I have and I am replanting to a larger tank. Good luck with your new tank! Let us know how it goes.


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## cs_gardener (Apr 28, 2006)

I think you could use the 20 gallon high if you kept floating plants to help diffuse the light a bit and use up the nutrients. I have a low tech, soil based 20 tall with 65watts CF that's doing very well with it's flotilla of red-root floater & Amazon frogbit. I do use glutaraldehyde regularly at low levels to add a bit of extra carbon.


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## ab420 (Feb 11, 2008)

That sounds like a plan! I'll use a good amount of floating plants to use up some of the light. 

Any recommendations for fast growing floating plants?


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## david f (Mar 24, 2006)

To ab420

Just a note on using soil,oxygen is very important for the bacteria functioning in your tank,using the deeper one would prove more difficult.I think bright lighting is good when sunlight is not always available.

Cheers David f.


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## bartoli (May 8, 2006)

ab420 said:


> I have a Coralife 24" 65 watt power compact light fixture sitting around, and want to use it for an el natural style aquarium. The tank will not get much sun light, if any...
> 
> My goal, is to run no equipment at all (other than the light).


Without CO2, a 65-watt light may be too much for a 20-gallon tank.


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## cs_gardener (Apr 28, 2006)

Some good, easy surface floaters are Limnobium laevigatum, (Amazon Frogbit), Phyllanthus fluitans (red-root floater) and Salvinia minima. Ceratophyllum demersum (hornwort) is another good floater that floats just under the surface of the water. You can leave Hygrophila difformis (water wisteria) floating instead of planting it. There's also duckweed, but I've come to view it as a plague so I'm not recommending it. 

If you also get some tall or large leaved plants like Nuphar japonica, red tiger lilly, some of the taller crypts, or maybe a smaller sword and let the leaves grow up, they'll help cut down on the light that gets in the tank. I just removed a large sword (leaves well over 2 feet long and about 3" wide) from a 33 gallon tank and suddenly there's LIGHT! I hadn't realized how much light that plant had been blocking until it was gone.


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## newbie314 (Mar 2, 2007)

Amazon Pennywort will travel across the surface. Neat plant.


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## aley1511 (Apr 23, 2007)

ab420 said:


> That sounds like a plan! I'll use a good amount of floating plants to use up some of the light.
> 
> Any recommendations for fast growing floating plants?


I have a 20 gallon high with 2 power compact bulbs totalling at 130 watts. It comes out to 6.5 watts per gallon. Yet I have difficulty growing glosso and other light demanding foreground plants because of the height of the tank. So don't worry about using floating plants to reduce the light intensity if you are planning to grow light demanding foreground plants such as glosso etc. The height of the tank already diminishes wattage considerably.


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