# How many Lumens?



## Katrina (Oct 15, 2004)

So I am getting ready to buy either a 20 or 29 g tank, it's going to be open, so my husband and I took a trip to Ikea yesterday to get some lighting for it. We bought two pendant fixtures and shades, and two bulbs. The bulbs are flourescent globes, the box says 1,000 lumens, so the tank will be getting 2,000 lumens. The shades will direct the light down, but I know there will be some light lost. I plan on having the lights about a foot above the tank. Will this be enough? I have some plants waiting for this tank, including: java moss, moneywort, Nymphaea lotus, Cabomba carolinia, wisteria, Rotala magenta, moss balls, and water sprite. I have no clue how to calculate the light in the tank.


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## pjhaddock (Sep 21, 2004)

I am not sure to answer your question, somone else should have more valuable info for you. But I have ~12,000 lumens or more over my 75G. But I have CO2 injection and can grow pretty much anything I want (I think). 2,000 lumens is less than 1 (one) 48" NO flourescent light, so 40watts. Not much light to be honest with you...

Philip


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## Rex Grigg (Dec 10, 2002)

I will say without doubt that it's not enough light. Unless you just want a fish tank. Take the wattage of the bulbs and then divide by about 4 in this case. That will give you an idea about the maximum amount of light you are getting into the tank.


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## Katrina (Oct 15, 2004)

Can someone tell me how many watts I need for a twenty gallon, while considering the light will be a bit above the tank? Does anyone have suggestions for attractive lighting for an open tank? I can't afford metal halide, just to get that out of the way. It's got to be flourescent.


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## Rex Grigg (Dec 10, 2002)

Take a few minutes and read my Guide. At a minimum you need 40 watts IN the tank. Note that how much you have over the tank doesn't mean squat. It's how much you get into the tank. I personally would run nothing less than a AH Supply 55 watt kit over a 20 gallon tank.


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## IUnknown (Feb 5, 2003)

> I plan on having the lights about a foot above the tank


I believe the only way you can do this is with MH. I think PC's should be less than 6 inches from the surface of the water.


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## malkore (Nov 3, 2003)

If the lights are a foot above the tank, you're losing about 75% of the intensity before it hits the water's surface. MH is gonna be the only option...and $250 for a MH setup on a 20gallon seems silly.


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