# Am I getting enough light with my CFL bulb?



## vtyou (Mar 17, 2012)

Hi all,

I was just wondering what range of lighting am I in with a tank that’s 35cm in height, with a single 23W 6500k 1600lumens CFL bulb attached to a regular gooseneck lamp sitting roughly 5cm above the tank? Not a densely planted tank, just an iwagumi tank


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## solarz (Aug 31, 2010)

Depends, how big is the tank? What kind of plants are you trying to grow?
35 cm is not very high, so the area immediately under the CFL will have enough light for medium-light plants. The surrounding areas, on the other hand, may only be able to support low-light plants.


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## infolific (Apr 10, 2016)

I've got two such bulbs over my quarantine tank which is half the height of your tank. They don't overlap too much so for any given spot they're probably about the same as your one bulb. I have a glass top so I'm losing some light there. 

They're enough to keep java moss and hornwort (floating) growing well. Other stem plants about 10 cm away don't die, but they grow very slowly until they get close to the surface and then growth speeds up. One plant that grows nice and bushy is Limnophila Sessiliflora. Floaters grow very well.

If I had to guess, I'd say you've got low light at your substrate, but you could still grow some plants.


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## vtyou (Mar 17, 2012)

solarz said:


> Depends, how big is the tank? What kind of plants are you trying to grow?
> 35 cm is not very high, so the area immediately under the CFL will have enough light for medium-light plants. The surrounding areas, on the other hand, may only be able to support low-light plants.


The tank dimensions are L50xD33xH35cm and I am mainly looking to grow monte carlo and maybe some rotala. I have another goose neck lamp laying but was just wondering if one bulb was enough to put me in the medium light range.


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## solarz (Aug 31, 2010)

vtyou said:


> The tank dimensions are L50xD33xH35cm and I am mainly looking to grow monte carlo and maybe some rotala. I have another goose neck lamp laying but was just wondering if one bulb was enough to put me in the medium light range.


I think it would give you low light.

To compare, 50cm is about 19". With a T5HO fixture, you'll need 2x18w bulbs to get medium light. That's 36w of T5HO compared to only 23w of CFL.

You could use 2 lamps, but it still wouldn't be as much light as the 2-bulb T5HO.


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## vtyou (Mar 17, 2012)

solarz said:


> I think it would give you low light.
> 
> To compare, 50cm is about 19". With a T5HO fixture, you'll need 2x18w bulbs to get medium light. That's 36w of T5HO compared to only 23w of CFL.
> 
> You could use 2 lamps, but it still wouldn't be as much light as the 2-bulb T5HO.


I would probably go with the 2 lamps as I already have them laying around, thanks for your help!

EDIT: Second question! Does anyone know if it's safe to use Miracle Grow's Nature's Care Organic Garden Soil with Water Conserve for a dirted tank?


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## rmahabir (Oct 6, 2014)

Hi vtyou,
There is a fish enthusiast out in the US named Pete Mang...very eclectic. He has a website dedicated to years of experimentation. His website will definitely put a very good perspective on your questions for lighting and the usage of Miracle Grow. If nothing else, it is a good read. www.lotsoffish.net


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