5600K vs 10000K

[yessongs]

Sorry double post

[coral reef]

65k is not the way to go , 65k is very close to sunlight yes but corals are not as close to the surface as they are in our tanks which means lots of that red spectrum you are giving them with that bulb they are not subjected to in the wild ,that red spectrum is mostly filtered out in the first 10 meters so it may make them grow but is not ideal for them , take a look at diving pictures do you see any white or yellows no what you see is blue if you are looking for a natural look go with a higher wattage and use 20k bulbs PS of coarse there is a exception to every rule there are some stoney corals that are very close to the surface but percentage wise no they are 15 to 50 meters down

[Von digity]

Originally posted by matt the fiddler

steve.. you are right   however- big urban legend....  and by your defination, the light chamber on a halide bulb is glass.   so why does that not filter it?

 

 

 normal glass will indeed filter [and some loss due to reflection]  only a small percentage of it-  we are talking closer to 10-20% of UV out instead of more the 95-97% UV glass removes..  i don't remember the exact numbers off hand- those are ballpark figures....... normal glass leaves enough there that the DEs unfiltered are still harmful..   especailly once you get in the 150W range..   can't imagine a 400 watt unfiltered-   ouch...

 

 

Matt, what I found out through OTF and my physics class is that all glass does indeed filter out UV. But here is where it gets all missinformed. UV light is categorized in 3 wavelengths, UVA, UVB, and UVC. Normal glass will filter out UVB and C. B & C are the ones considered dangerous. UVA and B are generally found all around us when we walk outside, and I'm sure it's found over reefs. So, normal glass should be fine. The only reason tempered might be good is becuase it is stronger, and may resist the high temp swings better. Another note is that UV glass really dampens the actuall PAR out put of DE bulbs, so maybe you don't want to over do it on the glass thickness and uvblocking characteristics. I'd like to see a table of DE bulb PAR levels under different types of glasses. I think it would be really rad if there was a way to get around it, too bad. DEs still rock compared to SEs.

[matt the fiddler]

that par test would be nice... hmmm any one here work at a glass factory/ hardware store..

 

thickness, type, etc should all be tested

 

 

well here is a link

 

http://www.advancedaquarist.com/issues/nov...02/feature2.htm

 

 

 

i have seen that normal glass only filters out UVB- both that and UVA are damaging in different ways- UVA can be to the eyes...

 

let me list a couple sources... runs to google.... more coming in an edit

http://www.uv-shield.com/faq.htm

 

 

*EDIT*

---------------------------------

The sun gives off ultraviolet radiation that we divide into categories based on the wavelength.

 

UVC - 100 to 290 nm

UVB - 290 to 320 nm

UVA - 320 to 400 nm

----------------------------------

 

UVC Radiation

UVC radiation is almost completely absorbed by the ozone layer and does not affect the skin. UVC radiation can be found in artificial sources such as mercury arc lamps and germicidal lamps.

 

 

 

so halide could be putting off UVC- need to check that out.. as sakis are technically mercury....

[Von digity]

Again, UVA and UVB are commonly found outside in everyday life. I don't think I'd trust info given from a website trying to sell a product. Most sunscreen only protects you from UVB. If UVA is really that damaging, then we'd all become vampires.

 

Also, even if a halide is putting out UVC, there is no way that it could pass through regular glass. Regular glass filters up to 330 nm. UVC is below that in the 290 and down.

 

Also, it has been discovered that the so called tempered glass used to shield the many uv emitting halogen regent fixtures is in fact regular soda lime glass. Just ask regent in an email what kinda glass you can use to replace a broken one on their products.

[winnker]

well, I just have to find a place to cut it in a round shape cuz the place I usually do does 90 angles only.

[birdman204]

Ummm.. Ok...

cellen - I am not saying this info is across the board. He only tested one wattage and type of bulb, It was simply that your conjecture was of the tone that I was a fool for trying to make a statement that was data driven. Using the general rule you stated that "20k's usually have less output" , one would deduce that most 13 - 15K bulbs would be better than 20k's, but many bulb manufacturers haven't quite been able to produce a product that reflects this assumption.

Coral Reef- MANY people are using 6,500's with much success in growning stony corals. When people use greenhouse farming operations, they aren't making tanks 10M deep. Have you been snorkeling off Hawaii (for example), the corals don't start 30 feet down. They are actually right up to the tide line. You are right in that Light above 600 nm is absorbed by the water at ~10M (but this too differs by location). But this means that some of this light is available above that depth. Why would you say it isn't useful, if some of the most densley packed, and most diverse Reefs are within these 30 feet. Many soft and LPS corals are also found at waters surface or in shallow lagoons.

 

Winnker, have you headed down to home depot to look at the Lexan XL acrylic, it has a high melting point, and has great UV shielding capabilities.

[Cellenzweig]

It was simply that your conjecture was of the tone that I was a fool for trying to make a statement that was data driven

Completely unintentional - sorry if it came out wrong.

[birdman204]

If I read it wrong, same to you. I think I already said it, but I run 20k's in my displays, but in a prop system, I run 10k's, and may soon switch to 6,500's for increased growth. Plus there are new studies linking increased pigmentation to the lower temp bulbs, but these studies are also showing more vibrant pigments with 20k's, so what's the answer? Without discussion, homegrown experiments and data, we'll just have to wait for others to figure it out.

[coral reef]

i agree with you 100% birdman and yes there are many corals on the tide line but most coral are down 15 to30m so in my opinion 20 would be ideal , and yes you will get better growth out of 65k but these corals on the tideline are only subjected to that intesity for short periods , which is my conclusion that corals should not be subjected to 65k all day long , and yes i have been diving in fiji 2 years ago and thats what i came up with. I must say this is a great debate and alot of nano reefers should gain some this tread

[Von digity]

I'd love to one day have a prop system with 6500k SE sakis burnt on magnetic DE ballasts or pfo hqi ballasts. The PAR should be really wild.

[DRZL-sauras]

time to revamp this thread...

[DRZL-sauras]

Coral reef has a really good point..why are 6500Ks held as the holy grail of growth? Ive been looking through diving pics and ive confirmed the unexpected...its blue down there!!. Also if you go to Dr. Mac's website you can see his lighting of choice are 400W 20K XM. I'd be hard pressed to say he has slow growth since he sells mostly aquacultured and his sps frag pack are all from prop colonies. Im not a whiter light hater and i do see the the PAR stats but how come? Maybe even though it has less PAR the PAR that is let out is the most efficently used? 'i.e. redder "unusable light is almost nonexistent in 20K and have a sharp peak around mid 400's. I doubt nature messed up and has corals lower than is optimimum.

[sdbeazley]

<- Well I guess you all know what I think.