CFLs that use 20 watt but put out the equivalent of 70?
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Old 03-03-2012, 02:48 PM   #1
Henri
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CFLs that use 20 watt but put out the equivalent of 70?


Hi everyone.
I'm setting up my DIY light system for my 20 gallon and I'm freaking out because I'm having a hard time finding the proper CFLs for it... I went to the hardware store the other day and the guy there showed me a bulb that uses 20 watt but puts out energy equivalent to 70... Do these kind of bulbs 'exist' or is he just trying to make money? Either way am I safe to put two of these on top of my 20 gallon or will I get TOO much light if they put out 70 watt of light? I'm dosing CO2.
Oh and my main concern, will I be able to grow any kind of plant with two of these bulbs, even if they don't really put out 70 watt of lights? This is killing me, I really want to set up a high light planted tank but I can't find any strong lights, the 50-60 watt ones are huge...
Thanks!
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Old 03-03-2012, 03:50 PM   #2
proaudio55
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You need to compare apples to apples. 70watts of incandescent light is roughly equal to 20w of CFL light. Incandescent's are sort of a benchmark that everybody compares to because CFL's are a replacement. . . going forward there will be less confusion because manufacturers are stating the light output in lumens. Oh, and the rule of thumb "2-3 watts per gallon" doesn't apply very well anymore. That was OK for T-12's but with T5's, LED's, and other high performance lighting . . . that's maybe a ballpark estimate.

For your setup, I would start with a pair of 6500K CFL's, 23w. That will put about 3200 lumens into the tank. It won't be super high power lighting, but it should be enough to get you started. If it were me, I'd add one more bulb: a 23w 2700K CFL for a total of 3 - 23w CFL's. . . But that's just me.


http://www.plantedtank.net/forums/pH...el_1_cropc.jpg


This is the rig that I used on my old 46 gallon:
http://www.plantedtank.net/forums/di...an-rhythm.html
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Old 03-03-2012, 04:55 PM   #3
Henri
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Quote:
Originally Posted by proaudio55 View Post
You need to compare apples to apples. 70watts of incandescent light is roughly equal to 20w of CFL light. Incandescent's are sort of a benchmark that everybody compares to because CFL's are a replacement. . . going forward there will be less confusion because manufacturers are stating the light output in lumens. Oh, and the rule of thumb "2-3 watts per gallon" doesn't apply very well anymore. That was OK for T-12's but with T5's, LED's, and other high performance lighting . . . that's maybe a ballpark estimate.

For your setup, I would start with a pair of 6500K CFL's, 23w. That will put about 3200 lumens into the tank. It won't be super high power lighting, but it should be enough to get you started. If it were me, I'd add one more bulb: a 23w 2700K CFL for a total of 3 - 23w CFL's. . . But that's just me.


http://www.plantedtank.net/forums/pH...el_1_cropc.jpg


This is the rig that I used on my old 46 gallon:
http://www.plantedtank.net/forums/di...an-rhythm.html
How do you know it puts out 70 watt of incandescent light? It doesn't say anything about that...
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Old 03-03-2012, 05:18 PM   #4
Daximus
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Quote:
Originally Posted by Henri View Post
How do you know it puts out 70 watt of incandescent light? It doesn't say anything about that...
You don't know. It's marketing. The only thing you can be sure of is that it's putting out 20 watts of CFL.

I think two of them would be fine over your 20 gallon, as mentioned above, you could probably do three of them.
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Old 03-03-2012, 05:21 PM   #5
GeToChKn
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I use 3 13w on my 20gal, found the 23w's too bright. General rate is roughly 4-5x the CFL is what normal wattage bulb would be.

13w ~ 60w
20w ~ 70w
26w ~ 100w
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Old 03-03-2012, 06:26 PM   #6
Henri
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Oh I get it now... I wish I read this post earlier, I thought they produced 70 watt of fluorescent light... I was affraid tht was too bright for my tank so I purchased two 5 watt bulbs that technically put out 25 watt of Light. So this light is incandescent? Aaagh :@ ... Ill go and return the bulbs tomorrow and get the two 20s...
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Old 03-03-2012, 07:42 PM   #7
Al Slick
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They're just trying to state that if you currently have a 70watt incandescent bulb at home than you should use 23 watt cf light to get roughly the same "brightness." If you were to replace all of your 100 watt old light bulbs with 100 cf bulbs they would be ridiculously bright. The packaging just tries to give you a rough estimate of how bright they will look in your home. Forget about the incandescent equivalent completely and just consider the actual wattage.
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Old 03-03-2012, 09:07 PM   #8
Henri
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Quote:
Originally Posted by GeToChKn View Post
I use 3 13w on my 20gal, found the 23w's too bright. General rate is roughly 4-5x the CFL is what normal wattage bulb would be.

13w ~ 60w
20w ~ 70w
26w ~ 100w
Are you able to grow high light plants well with 3 13w?
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