# LED vs CFL



## Nelsonfeelscool (Apr 3, 2019)

hey, all,

I have spent some time at the forum, learnt a lot from experts. But this question of LED vs CFL really bothered me... In the need to know the best lighting solution, especially I am going to have another tank. I wanted to ask the simple way, why cfl is suggested? 

right now I have 5g nano, with an 11w CFL, it literally sits on the tank lid, I am not sure if this is ok, but the plants growing great, fish also thrive. On the other hand, I have some rotala, which I want to bring the red colour out of them. 

So I searched ways to do so, and this specific planted led light is one way that I found online (image attached, sorry for the Japanese, the essential info should be enough) The manual suggested to have the led at least 20cm away from plants...exactly the opposite of my setting...

By learning from hoppycalif and researching the PAR for LED in the same tank setting. I just could not get a satisfied answer and I don't want to waste money... 

Therefore, I guess the two questions here would be: 
1. Is LED and CFL using the same equation for NPT (2W per gallon)?

2. Should I actually not to have my light on the lid, even though everything seems alright?


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## mistergreen (Mar 3, 2007)

The light's PAR output is the important thing. Watts/Gallon is irrelevant with modern lights like LED, CFL, T5, etc...

You're growing plants fine (in balance) with CFL but your goal now is to get the rotala to turn red? If so, this mean you'll need to go out of balance like more PAR, less nutrients. This is fairly dangerous goal in a NPT since you're not adding CO2 into the equation. You'll likely get an algae outbreak.

Removing your lid will give you a little more PAR with your CFL but water evaporation will be more.

If you want a cheap solution, why not get a 22W CFL to see if things work out before buying more expensive LED bulbs?


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## Michael (Jul 20, 2010)

CFLs are being phased out as they are replaced by LEDs which are more efficient and do not have the toxic waste (mercury) associated with CFLs.

A lot of my tanks still have CFLs over them, but as they burn out, I am replacing them with hardware store LEDs. To get about the same amount of light, I try to find LEDs with half the wattage of the CFLs I was using. For example, my 15 to 20 gallon tanks have two 13w CFLs. I replace them with 6w LEDs.


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## hoppycalif (Apr 7, 2005)

You can buy a cheap lux meter, like https://www.amazon.com/123CityFarme...=digital+lux,undefined,199&sr=8-2-spons&psc=1 and use it to measure the light intensity in lux instead of PAR, at the distance your light is from the substrate, *out in the air, not in the water*. Divide the lux by 70 and you have a good enough reading of the PAR you get with that light on your tank. You should aim for about 30 to 40 PAR - 2100 to 2800 lux. I think $20 is a small investment for being able to make good enough judgments about how much light you have.


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## Nelsonfeelscool (Apr 3, 2019)

mistergreen said:


> The light's PAR output is the important thing. Watts/Gallon is irrelevant with modern lights like LED, CFL, T5, etc...
> 
> You're growing plants fine (in balance) with CFL but your goal now is to get the rotala to turn red? If so, this mean you'll need to go out of balance like more PAR, less nutrients. This is fairly dangerous goal in a NPT since you're not adding CO2 into the equation. You'll likely get an algae outbreak.
> 
> ...


I like the idea! thank you... I think I have been looking at other's scape too much lately, that most of them are high-tech, which the red plants are just looking gorgeous ...Couldn't help myself wanting to try some else is capable of my budget, lol... IDK if I will every try co2, maybe the new 60cm(20Ggallon.)


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## Nelsonfeelscool (Apr 3, 2019)

Michael said:


> CFLs are being phased out as they are replaced by LEDs which are more efficient and do not have the toxic waste (mercury) associated with CFLs.
> 
> A lot of my tanks still have CFLs over them, but as they burn out, I am replacing them with hardware store LEDs. To get about the same amount of light, I try to find LEDs with half the wattage of the CFLs I was using. For example, my 15 to 20 gallon tanks have two 13w CFLs. I replace them with 6w LEDs.


Thank you! half of the W of CFL, great! that clears my question!

just curious, two 13w for 20 gallons is enough at all? so in that case, I am getting a 20 gallons tank, will a single 20W led be enough then?


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## Nelsonfeelscool (Apr 3, 2019)

hoppycalif said:


> You can buy a cheap lux meter, like https://www.amazon.com/123CityFarme...=digital+lux,undefined,199&sr=8-2-spons&psc=1 and use it to measure the light intensity in lux instead of PAR, at the distance your light is from the substrate, *out in the air, not in the water*. Divide the lux by 70 and you have a good enough reading of the PAR you get with that light on your tank. You should aim for about 30 to 40 PAR - 2100 to 2800 lux. I think $20 is a small investment for being able to make good enough judgments about how much light you have.


Thank you man! always a great helper!


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## Michael (Jul 20, 2010)

"just curious, two 13w for 20 gallons is enough at all? so in that case, I am getting a 20 gallons tank, will a single 20W led be enough then?"

You need two so that the light is spread over the entire tank more evenly. And my tanks are Walstad tanks with low to medium lighting. If you want high light, add wattage or more LEDs.


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## tiger15 (Apr 9, 2017)

CFL has lower efficiency and life expectancy than led, and it loses more efficiency after the first year. LED also shows better color on fish and plants if you select high K value with red and blue. No wonder CFLs are on the way out. All my aquarium lights as well as my household lights are now LED.


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## Nelsonfeelscool (Apr 3, 2019)

tiger15 said:


> CFL has lower efficiency and life expectancy than led, and it loses more efficiency after the first year. LED also shows better color on fish and plants if you select high K value with red and blue. No wonder CFLs are on the way out. All my aquarium lights as well as my household lights are now LED.


interesting point, actually I am swapping the current 11w CFL to a 5w or an 18W LED to see what's different, ofc 18w will be mounted way far from the tank


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## Nelsonfeelscool (Apr 3, 2019)

Michael said:


> "just curious, two 13w for 20 gallons is enough at all? so in that case, I am getting a 20 gallons tank, will a single 20W led be enough then?"
> 
> You need two so that the light is spread over the entire tank more evenly. And my tanks are Walstad tanks with low to medium lighting. If you want high light, add wattage or more LEDs.


I see! in fact, the new tank will be a south America black water tank, so I guess a single 18W should be enough for the feel. I always wonder if the light is the key to a better plant coloration, maybe next time I should try an outdoor NPT tank to test it out.


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## Nelsonfeelscool (Apr 3, 2019)

So a small update on the topic.

I did switch my 13w CFL to a controllable LED, ONF NANO, which it has 25% in incremental steps up to 100% output.

with that, I believe there is more algae problem than I had before, but it is not out of control. GDA is more visible but in the corner where the Glossostigma hasn't covered it(Algae out-compete plants growth). Other than that, the Staghorn Algae always happen no matter what light I have.

Rotala is actually more red and growth of the plants are better.


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## Reediculous_nanotank (Jan 12, 2019)

Nelsonfeelscool said:


> So a small update on the topic.
> 
> I did switch my 13w CFL to a controllable LED, ONF NANO, which it has 25% in incremental steps up to 100% output.
> 
> ...


Sound like it's working out pretty well! I'm curious because my set-up is also a 5g Walstad tank, what power level is your ONF nano set to?


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## mistergreen (Mar 3, 2007)

What? $100+ LED for a 5gallon tank.... You have money to spend.


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## Nelsonfeelscool (Apr 3, 2019)

Reediculous_nanotank said:


> Sound like it's working out pretty well! I'm curious because my set-up is also a 5g Walstad tank, what power level is your ONF nano set to?


i am at 75% and about 10 cm away from water surface hence the glass lid, because Hoppy said only 2100-2800 lux would be enough.


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## Nelsonfeelscool (Apr 3, 2019)

mistergreen said:


> What? $100+ LED for a 5gallon tank.... You have money to spend.


Took the easy way out, I guess lol. I just wish to have a good result, light might the only thing without any hustle, put it on and done. Actually got a lucky trade from a friend, so its's about $60, and that comparing to $10 CFL x 6...so hopefully the LED works for 6 years at least.


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## hoppycalif (Apr 7, 2005)

Nelsonfeelscool said:


> i am at 75% and about 10 cm away from water surface hence the glass lid, because Hoppy said only 2100-2800 lum would be enough.


I think you misunderstood my recommendation of 30-40 PAR, or 2100-2800 lux, not lumen. You need a lux meter to determine the lux your light produces at the substrate level in the tank. You can buy a $25 digital lux meter on Amazon or other websites, and measure the lux with no water in the tank, then multiply that by 70 and you have a rough measurement of PAR. Actually, you get a bit more PAR with water in the tank, but that requires the glass sides and ends be kept very clean, inside and outside. That causes the light that strikes the inside of the glass sides to reflect back to the substrate.


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## Nelsonfeelscool (Apr 3, 2019)

hoppycalif said:


> I think you misunderstood my recommendation of 30-40 PAR, or 2100-2800 lux, not lumen. You need a lux meter to determine the lux your light produces at the substrate level in the tank. You can buy a $25 digital lux meter on Amazon or other websites, and measure the lux with no water in the tank, then multiply that by 70 and you have a rough measurement of PAR. Actually, you get a bit more PAR with water in the tank, but that requires the glass sides and ends be kept very clean, inside and outside. That causes the light that strikes the inside of the glass sides to reflect back to the substrate.


Sorry my mistake, it is for sure sitting at 2750 lux at the substrate level. the front and one side of glass is clear, so that adds little more i guess.

P.S I am at work now, later I will post a picture


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