# Question about lighting



## Violie (Feb 27, 2010)

I have two 9 watt spiral florescent bulbs in my 10gal tank, one on either side of the hood.

While the total 18watts would be good normally, I read somewhere that the spirals don't put out as much wpg as non-spirals.

I just want to know if my lighting is sufficient for low-light plants. If not, what are my options as I think the next light up is 15watt. I don't want so much light that I have to start worrying about CO2 and fertilizers. Could I have one 15watt bulb and one 9watt? This would make the lighting uneven, but is that a bad thing?


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## igor.kanshyn (Jan 14, 2010)

Violie said:


> I have two 9 watt spiral florescent bulbs in my 10gal tank, one on either side of the hood.
> 
> While the total 18watts would be good normally, I read somewhere that the spirals don't put out as much wpg as non-spirals.


I don't think that spiral gives less light. This light is just not distributed so well as a light from a tube. But it's still good. Refrector is more important thing here.

Your light should NOT shine out of the tank and whole fixture should not get hot a lot. In this case your reflector is good.

15W for 10 gallons will be OK as a low light.
Think about plants you are going to keep there.


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## Darkblade48 (Jan 28, 2008)

Spiral CFL do not give out less light per se, it is just that there is less useable light due to the shape of the bulbs. There is significant restrike from spiral CFL bulbs compared with straight CFL bulbs (or even fluorescent tubes). 

However, with a total of 18W of CFL bulbs over your 10g, you should still have enough light to grow low light plants.


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## Violie (Feb 27, 2010)

Darkblade48 said:


> Spiral CFL do not give out less light per se, it is just that there is less useable light due to the shape of the bulbs. There is significant restrike from spiral CFL bulbs compared with straight CFL bulbs (or even fluorescent tubes).
> 
> However, with a total of 18W of CFL bulbs over your 10g, you should still have enough light to grow low light plants.


Well here's my concern, in my 5g, all my plants are lush, green, and growing. In my 10g, they are pale in comparison, and though growing, it is slower.

I don't know why, the only difference is the lighting and that my 5gal has 60% inert substrate, 40% flourite, and my 10g has 100% flourite.

I don't know why my plants aren't thriving like they are in my 5gal.


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## igor.kanshyn (Jan 14, 2010)

And plants are there? They might be not a 'low light' ones


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## Violie (Feb 27, 2010)

Both tanks have the exact same plants. All listed to be low-medium lighting. Both tanks have (in theory) the same amount of light. 9w/5g, 18w/10g


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## igor.kanshyn (Jan 14, 2010)

I think there is no magic  There is something else then substrate and light that matters in your case.

What fishes are there? Do they make an equal amount of waste (nutritions for plants)?
What filtration do you use?
What is your water change schedule?


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## Darkblade48 (Jan 28, 2008)

Violie said:


> Both tanks have (in theory) the same amount of light. 9w/5g, 18w/10g


Unfortunately, lighting does not work this simply, especially for smaller tanks. Don't forget that this WPG ratio that you are getting does not really work for smaller tanks, so while both tanks seem to have 1.8 WPG, the actual amount of light may be different.


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## Violie (Feb 27, 2010)

The spiral bulbs have a 6500K rating, if that helps, and here are some pictures:

















This one shows it next to a healthy plant that I was growing in my 5gal.

Do you think the plant would benifit from higher wattage? Or perhaps the non-spiral type bulbs? The next level of lighting I believe is 15watts. I just don't want to provide too much light have to start worrying about CO2 and ferts.


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## Violie (Feb 27, 2010)

igor.kanshyn said:


> I think there is no magic  There is something else then substrate and light that matters in your case.
> 
> What fishes are there? Do they make an equal amount of waste (nutritions for plants)?
> What filtration do you use?
> What is your water change schedule?


No fish, but just finished a fishless cycled, going to add a dwarf gourami and six or seven cardinal tetras.

I have an aquaclear 150 for filtration. I have the foam insert and some filter floss in it.


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## bae (May 11, 2007)

I think you'll be okay once you get some fish in there to provide nutrients. Najas is a very adaptable plant.


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## igor.kanshyn (Jan 14, 2010)

That's right. Do not make quick suggestions. Look how it is going for some time.


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## ksimdjembe (Nov 11, 2006)

give the tank some time. get a couple of fish in there to help feed the plants as Bae said.
the only thing I can think of, might be that the bulbs are not the type you want.? maybe you could get two 'daylight' bulbs - the spectrum seems a bit more bright and might help the plants?


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## Darkblade48 (Jan 28, 2008)

ksimdjembe said:


> the only thing I can think of, might be that the bulbs are not the type you want.? maybe you could get two 'daylight' bulbs - the spectrum seems a bit more bright and might help the plants?


This should not be the case. The spectrum of bulbs only refers to how bright humans perceive the light to be (i.e. a Daylight 6500K bulb would appear brighter than a 4500K bulb to us, but not necessarily to plants).


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## Violie (Feb 27, 2010)

Alright, I'll get back to you guys in a few weeks. I'm homing a dwarf gourami in the tank on Monday and will start quarantining some cardinal tetras the same day if I can get a quarantine tank (hello rubbermaid bin).


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