[aaron]

I have a question for a scientist who actually knows about light / solar radiation:

My friend has a coral farm in Sydney in a glass house. The light that originally came into the greenhouse through the clear roof was absolutely off the charts, far too intense for corals that are used to living in aquariums lit by artificial light. The current solution has been to paint white lime on the glass to block and defuse some of the light and this is working fine but we were wondering if it would be more beneficial to cover the glass roof in some kind of actinic blue film. and this leads me to my actual question:

Would such a film be blocking other colours in the light spectrum allowing more in the actinic range to get to the corals, or does the blue film actually absorb the blue spectrum, which is why it appears blue to our eyes?
I would be interested to hear from anyone with natural light aquarium experience or a background in this kind of thing.

[mray]

Blue film absorbs every color except blue which is why we see it as blue.

[Marteen]

From what I've read about natural light aquariums you should shade your corals for a few weeks to months initially but they will eventually adjust to the natural light.

[TimberTDI]

Originally Posted by Marteen

From what I've read about natural light aquariums you should shade your corals for a few weeks to months initially but they will eventually adjust to the natural light.

Marteen, I'm going to imagine that Aaron's friend is propagating corals to sell. If this is the case adjusting the corals to natural light could be detrimental when it goes back under artificial lighting.

Aaron,
You're probably going to have just do some trial and error and see what works best. Remember that most color films only allow 35 o/o of the light through.

Steven

[sjsoto]

i use natural light. coming in from west, north west, and south west. now for summer months noticed light to intense at afternoon till close to sunset. to alleviate problem, i used thin white curtains to cover windows, they are extremely thing since i still want to let some light in, and with designs with holes to let some in without being covered by curtain.

do you have any pics of the glass house?

[prattreef]

Aaron, I'm sure Sanjay can answer this for you in a fair amount of detail, but you will have to wait until he returns from India and I'm not sure when that will be exactly as his dad just passed away. We are talking days to weeks, not more than that.

[aaron]

Thanks Randy, I was hoping Sanjay was around. That's too bad about his father.
It's no rush, just something we starting talking about a few weeks ago and I thought I would turn the question over to some one who actually knows what they are talking about.
My friend is propagating coral for use in his aquarium maintenance business, so they will return to MH lighting once they have grown out. Its currently winter here in Australia, so light levels are not as critical for at least a few more months.

[cali_reef]

I don't know anything about natural sun light, but I have seen two large outdoor prop systems in Southern California. Both needed to be cover with fiberglass roofing panels as the sun rays were too strong for the depth of the ponds\tanks the corals were kept.

[jejton]

There are a couple of threads on RC by coral farmers who set up here in the US and their trials with different solutions for your very problem.

[SevTT]

I think you might be better off with a neutral density filter than a colored one. That is, neutral grey film, or, heck, netting/screening of appropriate densities. That way, everything gets the full spectrum, just less of it.