Light Spectrum

Hi there, it seems my fluorescent bulb, which is for aquariums, is drowning out the colors in my background something awful! I can’t remember how it used to be or when I changed bulbs, although the tank looks great!. I’m on a second background and the same result. Anyway, can someone recommend a good bulb with the right color spectrum so can I can avoid this?

thanks!

look for globes with a 6500K rating. (K is for Kelvin).

I will look into it.
Thanks!

bigrob126 said:

fluorescent bulb,

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They need to be replaced every 8 to 12 months depending on their quality.
Or changer over to LEDs.

@bigrob126 you can't beat LED i have Fluval ones on both my tanks and you can adjust the lighting to suit yourself plus you can get reasonable priced ones from amazon.

https://www.amazon.co.uk/s?k=aquari...s,aps,171&ref=nb_sb_ss_midas-iss-sm_1_19&tag=

Thekelvin rating of light just indicates the color tine of the white light. a high kelvin rating indicates a blueish white light. a lower reading indicates a yellow white or reddish white light. The Kelvin rating is not a measure of spectrum. I personally prefer a kelvin rating of 3000K.

What you want to look for is a CRI (color rendering index). This is the only measure of spectrum you will find on buulbs. A reading of zero means you bulb is only producing one color of light. a Color rendering index of 100 ( the highest reading possible) means the colors you see with the light will look exactly the same if you replaced the light with the sun. A high CRI bulb produces as many colors of light as possible.Zo high CRI bulb will have a better spectrum than a low CRI light.

Unfortunately many manufactures don't post CRI number their bulbs. Today many LED lamps are 70 to 90 CRI. So for your aquarium You want to look for a 90CRI flouroescent bulb.

example 1
Example 2

StevenF said:

I personally prefer a kelvin rating of 3000K.

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How about 6500K ? Is it too much ?
Do you think CRI is also important ?

sunlight has a 5500-6500K rating so 6500K is as close to natural light as you can get. Just make sure it has red and blue light for plant growth.

Avel1896 said:

Do you think CRI is also important ?

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It is more important than the kelvin rating. You cannot have a high CRI if you don't have red or blue light. While red and blue light is very important for plant growth many plants also need yellow and green, orange and violet. Some plants simply don't do well with just red and blue light. The higher the CRI there likelyyou have all colors of light.

StevenF said:

It is more important than the kelvin rating. You cannot have a high CRI if you don't have red or blue light. While red and blue light is very important for plant growth many plants also need yellow and green, orange and violet. Some plants simply don't do well with just red and blue light. The higher the CRI there likelyyou have all colors of light.

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Recapping :
- CRI above 90.
- between 5000 and 6500 °K.

What about the PAR ? When I comes to PAR, I'm lost

Is this good for aquarium plants ? Or should all colors be at the same level?

It's preferable to have equal peaks of red and blue but that colour spectrum is close enough to be fine

Avel1896 said:

Recapping :
- CRI above 90.
- between 5000 and 6500 °K.

What about the PAR ? When I comes to PAR, I'm lost

Is this good for aquarium plants ? Or should all colors be at the same level?

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PAR there are 2 aspect to PAR

1. It specifies that the spectrum used by plants is 400 to 700nm
2. PAR also refers to the brightness of the light in number of photons hitting a given area over period of time. Unfortunately many light manufactures to don't list the brightness in PAR units Normally lights bightnessare listed lumins, Lux. I wouldn't worry about the PAR brightness measurement. Also PAR meters are expensive and hard to find. In my opinion it is much more important to insure that whatever light you use has a dimmer built in. That way you can adjust the light as needed.

if you assume each nanometer of the PAR spectrum is one color then between 400 and 700nm there are 300 different colors. High CRI lams have more colors than low CRI lamps.

The Kelvin rating is referring to a block of metal that is heated until it gets white hot. Kelvin is measrement of heat or temperature. Thehigher the temperature of metal the bluer the with light. At a lower temperature the metal emits a redder light.

INcandecent bulbs have tungstan filament heated until it is white hot. The incandescent bulb emits are particular spectrum. but it is not energy efficient.

LEDs andFluorescent bulbs generate light differently but are more energy efficient. But the spectrum will look very different than that of an incandescent bulb. But the Kelvin rating for lamps has been used for so long that all lamps have a kelvin rating so that people know the color tint of the light.

The spectrum graph you posted is a calculated graph of the light absorbed and how effectively the plants use that light. You won't find a lamp you can buy that has that spectrum. Also lamps don't produce a a spectrum with each color at the same level.

this link has a image with the spectrum of several different lamps, the the sun spectrum. Overall buy a high CRI light with the color temperature YOU want with a dimmer.

Many thanks @StevenF