Light wattage question

[mitek2]

I know the new thing is LED lights, and one day I will have those I hope. In the meantime I have power compacts. My question though is if a 55 W actinic gives off the same radiation or acqilable light as a 10k white.
I know the K rating is the spectrum or color of light. Since actinic and 10 K are both 55 W could I replace one for the other and have the same watts per gallon of functional light. I'm trying to create more blue but I don't want to lose my output in the process

Thanks!!

 

[soeminpaing]

I am no expert but I think PAR output of blue LED is very low compare to white LED.

 

[Ron Reefman]

I am no expert but I think PAR output of blue LED is very low compare to white LED.

soeminpaing, please don't take this the wrong way, but you are right, you are not an expert.

PAR has very little to do with the spectrum. PAR is Photosynthetically Active Radiation. Different kinds of plants use different spectrum of light to do photosynthesis so PAR is made up of all visible light that plants use.

The zooxanthellae (algae) that is inside our coral's polyps use more blue spectrum than any other to do photosynthesis so it can grow and feed the coral.

To the OP: I'm not sure what it is you are asking? The K ratings isn't exactly about spectrum as much as it is about the mix of a lot of spectrum that we use to describe how warm or cool (redish yellow to blueish) our 'white' lights are. Spectrum is the wavelength of a particular color, i.e. violet is in the low 400nm range and red is in the high 600nm range.

If you are asking will the 55w blue fluorescent tube be as useful to the coral as the 55w white tube? It will probably be better for it.
If you are asking will it light up the tank as well for you to see? It won't be at 'white' and probably not as bright. But your coral will 'see' more useful light energy.

Just know that it doesn't take much 'white' light to wash away the blue that our eyes see. But just because our eyes don't see it, doesn't mean the blue spectrum isn't there for the coral, it is.

 

[mitek2]

Great thanks. That's exactly what I'm asking. My tank has so much white I think I'm losing a lot of color. I have 2- 55w PCs where one side is 10K and one side is actinic. I think I'm going to take one out and put in an all actinic.

That would give me 1- 55w PC that is all actinic, and 1- 55w PC that is half 10K and half actinic.

Do you think that would give me more color, but still give the corals the light energy they need?

I have a Red Sea max C130 cube. It is 34 gallons and maybe about 24 inches deep.

 

[dkeller_nc]

I use PCs over my 20 gallon nano that was setup in 2004. I went through a number of combinations within the first year of having the tank set-up. The best compromise I came up with was to use one 65w 10k/460nm combination bulb, and one dual 460nm 65w bulb.

The 460nm bulbs put out a lot more visible light than the 420nm bulbs, so the tank looks brighter and has a better visible color balance than when I used a dual 10k/460nm and dual-actinic bulb.

You might have to hunt around for a straight-pin 460nm bulb. All PC bulbs are getting harder to source as sales of the fixtures continue to go down in favor of T5HO and LED, but one of the best places to get bulbs of all types is Champion Lighting and Supply.

 

[soeminpaing]

Light wattage question

I come from planted tanks so I dont have much knowledge on what spectrum corals use. Since you said blue fluorescent tube is better than white fluorescent tube can you explain a little more . Will coral growth be better if we use blue light only? I always thought they need wider spectrum like plants. I thought since most SPS people are obssed with PAR. I thought low PAR output from blue light might hinder growth. I always assume white for growth and blue for color. Can you point out flaws in my logic.

 

[nickdo]

I come from planted tanks so I dont have much knowledge on what spectrum corals use. Since you said blue fluorescent tube is better than white fluorescent tube can you explain a little more . Will coral growth be better if we use blue light only? I always thought they need wider spectrum like plants. I thought since most SPS people are obssed with PAR. I thought low PAR output from blue light might hinder growth. I always assume white for growth and blue for color. Can you point out flaws in my logic.

wrong,
for example, ati blue t5ho provide more PAR compare to ati white t5ho.

it is not about the color or spectrum. your pc won't provide enough PAR in 24inch height.

 

[Ron Reefman]

I come from planted tanks so I dont have much knowledge on what spectrum corals use. Since you said blue fluorescent tube is better than white fluorescent tube can you explain a little more . Will coral growth be better if we use blue light only? I always thought they need wider spectrum like plants. I thought since most SPS people are obssed with PAR. I thought low PAR output from blue light might hinder growth. I always assume white for growth and blue for color. Can you point out flaws in my logic.

Using blue only can work, but just like white only, it's not the best option. Here is a graph of the spectrum of light that corals use:



As you can see in the graph, chlorophyll A & B which are responsible for photosynthesis in the zooxanthellae (algae) in our corals, use way more blue spectrum and only a small spike in the red spectrum. This is partially due to the fact that blue light penetrates the water better than other spectrum, so the plants have adapted over time to work differently from terrestrial plants.



I think you might have some kind of a misunderstanding of PAR. Blue spectrum light is NOT lower in PAR than any other spectrum. It may look less bright to our eyes, but that has nothing to do with how much light energy there is. Consider UV which our eyes can't even see, yet it can burn our skin. The shorter the wavelength of the light, the more energy it has.

SPS corals do want more PAR than most other corals, but that doesn't mean more white. Since most corals in our tanks prefer more blue spectrum and SPS corals want more PAR, that means they want more light energy. As in more powerful lights or even just more bulbs. Thus we go from 150 watt MH to 250W MH to 400W MH or we go from 1 bulb to 2 or 3. LED and fluorescens work the same way. Really crappy leds use 0.3w leds, good fixtures use 3.0w leds and expensive ones use clusters of leds that have even higher demands.

I hope that helps? And if you have questions, I want to try and help.

wrong,
for example, ati blue t5ho provide more PAR compare to ati white t5ho.

it is not about the color or spectrum. your pc won't provide enough PAR in 24inch height.

What makes you think a PC fluorescent bulb fixture can't reach 24" deep? Back when PC was the fluorescent of choice people used them all the time. Try testing it with a PAR meter. A PC fixture is kind of old school in 2015, but that doesn't mean it doesn't work.

 

[soeminpaing]

Thanks for detail explanation. I saw some PAR 38 bulbs with different configuration of color. The wattage is all the same but all blue configuration specifications has less PAR on their website than white counterpart. That's why i just issume blue has less PAR. I personally prefer bluer spectrum but worry about starving the corals. I am considering a Par38 for a small zoas frag tank and deciding to go all blue or full spectrum. The info helps me a lot.

 

[Ron Reefman]

Glad to try and help out. I struggled with this stuff for a year or more when I was first getting into leds about 4 years ago.

The manufacturer you mentioned is right. The white bulb has more PAR than the blue bulb. But if the corals are only using 20% of the PAR from the white bulb and 100% from the blue bulb... see what I mean?

And I still want white in my tank so it looks more natural most of the time. However I do go very blue at early sunrise and late sunset.