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Discussion Starter · #1 ·
Hello,

I've got a 40inch long, 15 inch deep aquarium. It used to have a single T8 light, but i could only keep plants with very low light requirements like java ferns, crypts, moss,...

Now i made a new hood with 5 CFL light sockets. The visual light is a LOT higher now, however. I read some articles that with CFL, it doesn't matter if i placed 2 or 3 or 5 lamps, the amount of light the plants get stays the same and it would only increase the area that is covered, making it useless in a smaller aquarium?

Any insights on this would be awesome.
 

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You need 8-10 of this bulbs for 2 rows and 4-5 of each row for at least 8 hours per day. Each light bulb is at least 23w CFL 6500K. Such amount lighting is enough for carpeting plants like Micranthemum 'Monte Carlo' and some red plants like Alternanthera reineckii 'Mini', even Rotala macrandra close to bulbs. Of course CO2 at least 40 bubbles per minute and some fertilizer are required.
The beauty of CFL is low bulb cost(e.g. 1600 Lumens at 23w for 5$), good quality of light vs LED, the intensity is manageable: some areas may have strong light, some may have medium light etc.
The downside of CFL usually the light fixtures are not neat and hard to hide.
 

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Discussion Starter · #3 · (Edited)
You need 8-10 of this bulbs for 2 rows and 4-5 of each row for at least 8 hours per day. Each light bulb is at least 23w CFL 6500K.
I dont think 10 lightbulbs would fit under the hood lol, i've got 3 on one side, and 2 on the other and its already pretty cramped in there, the spiral lightbulbs are rather large. will add pictures.

Anyway, so that means the information i found was wrong and u can stack CFL's to get a higher PAR in the tank?
 

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Start with smaller bulbs first, or you will be harvesting the algae you seed now by using too strong light.
The most important factor is how close you can get with those bulbs.
As long as I stay within a certain distance I am able to carpet glosso with an 8W spiral CFL without it climbing up.
 

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Nice to have more info about the tank. Tell us what is the height of the tank (15 in?)? What is the depth (front to back) of the tank? The total volume of the tank? What kind of plants you plan to grow?

The hood you made is pretty neat and I think you are pretty close to a nice set up and some suggestions:
1) use some kinds of reflectors can give you 40% more light towards to the plants.
2) use fans if the fixture is hot
3) use glass canopy to prevent humidity. Important for safety!
4) I thought you installed the bulbs vertically, which is designed for. The current position may not good for deep tank.
5) I see there is a plenty of rooms for more bulbs. CFLs are like any light source: the denser they are grouped the brighter they are and more light will reach the bottom, more PARs.

What you have read was correct. E.g. A 23W CFL with good reflectors should be good enough for most of planted tanks for 8" circle of bottom areas for 13" height, what you need to do is to cover more areas using more bulbs. It is hard to concentrate 10 of CFLs to one 8" area for a stronger light for corals for CFLs. But for the same watts you can easily do with MHs or some kinds of LEDs. They can be made denser than CFLs.

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Start with smaller bulbs first, or you will be harvesting the algae you seed now by using too strong light.
The most important factor is how close you can get with those bulbs.
As long as I stay within a certain distance I am able to carpet glosso with an 8W spiral CFL without it climbing up.
Could you share with us what is the certain distance? Helpful for designing a planted tank. Thanks.
 

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Discussion Starter · #6 ·
height is 15 inches, depth is 12 inches(I live in europe so i use a metric system so the conversion to inches is roughly estimated). Volume would be about 100 liters or 26.4 gallon


1) use some kinds of reflectors can give you 40% more light towards to the plants.
I plan on painting the inside of the hood completely white with a water resistant furniture paint, that should increase the reflection. I am currently using aluminum foil as reflectors, but its not as neat.

2) use fans if the fixture is hot
Fictures are not hot, the lid is, but that'll be a lot better when its painted white.

3) use glass canopy to prevent humidity. Important for safety!
Humidity isn't that bad actually, i was worried about that at first too, but its all pretty dry, and there's a built in safety, if it gets wet and could shortcircuit or something the power to the hood is just going toi shut off.

4) I thought you installed the bulbs vertically, which is designed for. The current position may not good for deep tank.
Using reflectors, putting them like that shouldn't matter too much? if you look at a lot of specifically designed aquarium lights with a clip on system for a CFL bulb, they use horizontal laying lamps?

well xD anyway good thing the tank isn't deep at all.

5)
I see there is a plenty of rooms for more bulbs. CFLs are like any light source: the denser they are grouped the brighter they are and more light will reach the bottom, more PARs.
Not sure if i can take the hood apart again, without breaking it lol xD I did not make the circuitry easy to access. both because its insulated around the circuitry and cracks would allow some moisture to get through

What you have read was correct. E.g. A 23W CFL with good reflectors should be good enough for most of planted tanks for 8" circle of bottom areas for 13" height, what you need to do is to cover more areas using more bulbs. It is hard to concentrate 10 of CFLs to one 8" area for a stronger light for corals for CFLs. But for the same watts you can easily do with MHs or some kinds of LEDs. They can be made denser than CFLs.
I chose CFL's for the exact reason that i like to do a lot of DIY and the initial purchasing price and preplacement cost.

Thank you for the tips though, I will surely use them!
 

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From my experience about CFLs, 5 bulbs still are not enough for such a tank. 8 is good, 10 is the best. Your tank is 40" long. You may add some LED bars or LED DIY chips found on Ebay. From your photos I suggest go to 6500K daylight bulbs. 2700K and 4000K, even 5000K have some green/yellow tint not good for plants but good for algae.
 

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Discussion Starter · #8 ·
From my experience about CFLs, 5 bulbs still are not enough for such a tank. 8 is good, 10 is the best. Your tank is 40" long. You may add some LED bars or LED DIY chips found on Ebay. From your photos I suggest go to 6500K daylight bulbs. 2700K and 4000K, even 5000K have some green/yellow tint not good for plants but good for algae.
Okay, i'll see what i can do, gonne wait to see how the current plants react though. as for 6500k.. they arent available here... unless in aquarium shops and its 50$ for a high wattage lamp there...

the "home depot" here only sells 2.7k, however, i have the same bulbs(just a single bulb) over several nano tanks and the plants there do great, so i wouldn't say they are not suited for plants. Also i've grown a LOT of plants emersed with just these bulbs, its the reason i went CFL, because my emersed plants did so great with these.
 
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