Actinics?

[vettesarebest]

I was wondering iff you need to replace actinics. I have always done it but i've herd the people don't and people do. Will it cause algae growth if you don't replace them? I know they are only for asthetic reasons but I am just wondering. If I don't need to might as well save the money.

 

[kevin]

You should replace florescent bulbs about once per year.

 

[vettesarebest]

Does this go for power compact bulbs as well? Do they loose intensity over this time? Why do we need to replace them if there only for asthetics?

 

[kevin]

Power compacts lose strength over time too. if they are just for asthetics, then I think you can go a bit longer, but it will increase algae growth as they lose strenght

 

[wbholwell]

I don't think actinics are only for aesthetics. I believe that spectrum of light is very important for many animals. I replace my PC bulbs every 12 months.

 

[vettesarebest]

I have been told that they are only for pleasure and to make the corals look brighter.

 

[wbholwell]

It's my understanding that because the "blue" end of the spectrum is closer to ultra-violet and the wavelength is smaller, it penetrates deeper into the water than other wavelengths. So many coral have adapted to using this end of the spectrum.

Correct me if I'm wrong, anyone

 

[cameron]

Blue is for photosynthesis... most photosynthesis takes place in the blue spectrum (very general I know there are exceptions and probably quite a few). I believe they are mainly used to boost lighting on lower kelvin setups. I am guessing once you cross into the 14k+ world they become less useful as you are getting plenty of light penetration.

I am not even close to understanding lighting fully as I haven't read the science on it yet, but most of the books I have read stay with the above theme.

 

[mojo]

Can you provide some evidence that says that photosynthesis uses the blue part of the spectrum? If so, there are plenty of coral and plant growers who have been missing out over many years...

The most coral growth comes from the yellow end of the spectrum - 5500k Kelvin, 6500k, up to 10,000K. Otherwise, corals would grow crazy with 20k bulbs and people would be scrambling to find 50k and 100k bulbs!

No, the actinics are for your enjoyment only. Replacement when they burn out- your corals will care not.

 

[cameron]

mojo wrote: Can you provide some evidence that says that photosynthesis uses the blue part of the spectrum? If so, there are plenty of coral and plant growers who have been missing out over many years...

I was just reading this article:

http://www.advancedaquarist.com/2002/2/aafeature">http://www.advancedaquarist.com/2002/2/aafeature</a>

which states:[QUOTE=]Researchers have addressed light quality and its effects on zooxanthellae and coral growth. Perhaps the most interesting is a paper by Kinzie et al. (1984); they presented evidence that corals grown more rapidly under blue and white light of the same intensities (~12% of solar Photosynthetically Active Radiation - PAR, ~250 µMols·m2·sec, or 10,000 lux) than under "green" or "red" light of equal intensities. These scientists used clear or colored acrylic filters and natural sunlight. The blue filter transmitted wavelengths of ~ 400 to 500 nm and the clear filter (transmission quality not shown in the paper) likely was a fair representation of sunlight (although most acrylics attenuate all wavelengths but tend to decrease violet and blue disproportionately). [B]"Blue" light is suggested to have some rather "magical" properties - it has been noted to increase rates of protein synthesis in some algae, as well as cause shifts in photosynthetic pigment concentrations in zooxanthellae. Blue light has also been reported to increase rates of photosynthesis (Kinzie and Hunter, 1987). [/B][/QUOTE]

I may have misunderstood what this meant, but I did state that my lighting knowledge is very limited.

 

[cameron]

I am trying to dig out my science book for photosynthesis in general, but that may not apply to corals.

 

[mojo]

Hmm- interesting. It's possible that instead of higher kelvin bulbs resulting in slower growth that they actually produce overall less light (in terms of PAR) than a comparable bulb with lower kelvin.

 

[vettesarebest]

Thanks Mojo! thats what I thought. Also I have a Coralife Aqualight Pro HQI fixture on my 75. When the HQI bulbs die I am thinking of running 14K on it. The fixture also has 96 watt actinics. Should I keep the actinics even with the 14K HQI's on there or should I change the actinics and put something else in?

 

[vettesarebest]

billbrown wrote: I have just purchased a new lighting fixture with (2) 250 watt (20,000) Halide and (4) 65w true actinic bulbs. They give the tank an ultra-blue appearance. My tank is cycling but I intend to add corals once it is established. Would lighting this high in the spectrum be contraindicated for keeping corals? If so, what would be a more appropriate range?

In my opinion that is too much blue spectrum and the corals will grow very slowly and I don't think they would be getting enough lower end spectrum light.

 

[mojo]

billbrown wrote: I have just purchased a new lighting fixture with (2) 250 watt (20,000) Halide and (4) 65w true actinic bulbs. They give the tank an ultra-blue appearance. My tank is cycling but I intend to add corals once it is established. Would lighting this high in the spectrum be contraindicated for keeping corals? If so, what would be a more appropriate range?

Oh boy- here we go... Lighting is as much about what you want to keep as it is your own taste. You've got the tank so you can look at it. If it's worth it to you to have slower growth but more blue, then go for it. If you want the best growth, get 5500k bulbs.

 

[mojo]

Maroons15 wrote: In my opinion that is too much blue spectrum and the corals will grow very slowly and I don't think they would be getting enough lower end spectrum light.

You're missing the point of this thread.... Facts would be more appropriate than opinion on this one...

 

[cameron]

mojo wrote: Hmm- interesting. It's possible that instead of higher kelvin bulbs resulting in slower growth that they actually produce overall less light (in terms of PAR) than a comparable bulb with lower kelvin.

I think I got it, but I could be WAY wrong. Actinic bulbs are "filtered" for lack of a better term which isn't the same as the true blue spectrum light. While actinic bulbs do produce an amount of useful blue spectrum light that can (and I read a couple threads at reefcentreal where it did) grow zoos, it is artificial and not the same intensity that the article was referring to. As you move up from 10k to 14k to 20k you get more natural blue spectrum fired into the aquarium which is apparently pure goodness and more of what that article was referencing.

It seems actinic can boost blue spectrum light and stimulate growth, but seems to be more of a decorative light since the filter reduces effectiveness in all other spectrums of the light given off from the bulb.

In short, seems mojo is correct and I misunderstood the article. I have to read more to shore this up as right now it is still rolling around in my head.

 

[vettesarebest]

Yeah misunderstood this. I miss worded that. Its a fact.

 

[washowi]

replace them...period..no more than 12 months...

 

[vettesarebest]

Mojo said not to replace them.. I don't know what to do?