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 Posted 1/31/2006 12:01:49 PM |
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... presuming the fluorescent lamps are no higher than 3" off the water 
.Anthony Calfo
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| Posted 1/31/2006 1:46:20 PM |
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Anthony Calfo (1/31/2006)
Despite quality of light form many fluorescents, what they lack is intensity. They have a weak punch. And anything over 3" off the surface of the water is really quite a waste of light. Its staggering really.
Yea that intensity drop over distance squared is pretty brutal. http://science.howstuffworks.com/experiment2.htm
In my experimenting with a light meter, I found reflectors can help a great deal. 'course MH already have reflectors, so it's not really an issue there. Can't buy any decent reflectors for T-8 bulbs, and those 'gull wing' reflectors for the T-5's are like the wheel - it doesn't get any better 
While not for everyone: I used up using strips of mirrored glass/acrylic set at 45 a degree angel for my DIY T-8's. Even then something like 1/4 of the light is wasted lighting the inside of my hood. I think reflectors helps not only making the bulb appear bigger to the tank but from collimation effects http://www.mellesgriot.com/glossary/wordlist/glossarydetails.asp?wID=186 - meaning the light photons are running parallel to each other. Like the light you get from a laser or from the sun.
My lights hang about 1/8" above the frame of the aquarium. No worries about a coned-shaped light pattern for this reef keeper! I clean them occasionally.
I've sorta toyed with idea of cutting back on the lighting actually. (waiting for the gasps of horror and cries of heretic to subside) I've found I can 'blow out' some of my favorite LPS coral when they're mounted where I want them. But for awhile anyway, now what I know what to look for, I'll browse my local LFS (who is a MH junkie) to find corals that are 'blown out' and offer to take these sickly looking corals off his hands (if the price is right). Maybe that way I can find an appropriate coral or two to finish the tank.
Got myself a nice Green/Purple rim Montipora sp. that way. Well it's Green/Purple in my tank - in his it was a sickly pale mint and tinged with a whisper of pink.
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| Posted 1/31/2006 3:12:18 PM |
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outstanding links and information Don! Thank you for your input as always
.Anthony Calfo
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| Posted 1/31/2006 3:12:37 PM |
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While I am more then happy to move the bulbs closer to the water, the dilemma I face is engineering this so that I can still easily feed, scrape algae, etc, without having to totally remove the canopy... If it helps, here's a pic...
And just as a note, I have doors for the canopy front that have not yet been installed.
Another thought/question - How much is it going to help me if I make the entire inside surface of the canopy reflective? Read: Perhaps maybe then can I avoid lowering the bulbs?
And thanks for the links! Gotta love HowStuffWorks.com...
Paul Thompson
South Ascot, Berkshire, England
Board - West London Reef Club
Webmaster - Central Oklahoma Marine Aquarium Society
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| Posted 1/31/2006 3:36:22 PM |
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| FWIW... my 4 VHO lamps for my 120 gall display sit right on top of the glass braces (touching) and are simply captured by a discreet hardwood collar that is piano hinged at the back. Access to the tank is short and sweet. Re: the reflector question... I'd really regret advising you to make a (hopeful) change when the numbers (lux reading) maynot bear it out. I really don't see how you/we can make up for the degredation of light through air to any significant extent. I'm still voting for lowering the fixture if a lux/light meter cannot be bought or borrowed (see photographer friends locally... they may have one to show/share or anyone you know by chance in the local Fish and Wildlife depts opr EPA? They do field tests and have the same gear for light measuring)
. Anthony Calfo
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| Posted 1/31/2006 3:38:17 PM |
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and BTW - very nice rockscape! Sweet And considerate of long term growth for the corals. It will be an incredible tank one day once grown in a bit.
.Anthony Calfo
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| Posted 1/31/2006 3:57:15 PM |
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Anthony Calfo (1/31/2006)
and BTW - very nice rockscape! Sweet And considerate of long term growth for the corals. It will be an incredible tank one day once grown in a bit.
Why thank you!
And I forgot to plug and comment upon the horizontal overflow running 48 inches along the back of the tank. That is why there is a lighter colored section at the top back of the tank. It's running beautifully - gotta it levelled well so that there is a nice 1/8 inch layer of water flowing over the entire overflow.
Paul Thompson
South Ascot, Berkshire, England
Board - West London Reef Club
Webmaster - Central Oklahoma Marine Aquarium Society
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| Posted 1/31/2006 5:10:27 PM |
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| I currently have 3x 250 MH and 6x 80W T5 over my 30" deep 150g. The T5's are up in the DIY hood/reflector with the MH which all are about 8" off the water. Here's a picture: 
My question is , if I were to support the T5's at about 5" below the MH to get the 3" off the water as suggested, what effect, if any, would the MH have shining through the T5 from above. It also seems that I wouldn't be able to bring down any reflectors for the T5's as they would surely block the MH. So, would I be gaining anything or going backwards? Thanks,
Rich New Jersey Reefers Club
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| Posted 1/31/2006 6:50:07 PM |
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| you raise a very good point Rich. While I really do not think the lowered T5 lamsp will cast much shadow or block much light (especially for strategic flanking of them on the far sides of the tank)... there is the issue of what is their value at all? The answer is... none. Not even aesthetic in practical terms since you can get MH lamps in almost any conceivable color/brand to satisfy your color preferences. And it is a stone cold fact IMO (shared by many others) that most every MH lamp of decent quality available in the hobby market has enough blue light in its spectrum to satisfy most any coral you are likely to keep... including the very "yellow" colored daylight (6500K) lamps. In short... MHs do not need any fluorescent light. Period. Pick your MH lamp carefully to meet your PAR and color needs, and unplug the fluorescents. To be clear here... I am not telling folks not to use fluorescents. Quite the contrary and as previously stated in this thread and others. I do use, enjoy and recommend fluorescent lights at times. Stand alone. But with MHs, I see no need to use fluorescents whatsoever beyond any very specific and purely aesthetic desire you may have. And as such, its rather irrelevent where they are placed short of not being an obstruction to you or the "good" lamps. So to answer your question specifically Rich - No, do not lower your T5s my friend.
. Anthony Calfo
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| Posted 1/31/2006 8:57:47 PM |
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Wandering back to the topic...
I cannot see the difference between sides of the eggcrate, however, I can feel it quite easily. So if you are staring at your eggcrate and turning it over and sideways and upside down... try closing your eyes and lightly "pinching" the grid through the holes, moving your fingers back and forth. Your fingertips may see the slight difference that escapes your eyes.
Wierd? Not to me, but they invented ultra high index lenses just for my glasses. 
Don't count your gobies before they've metamorphosized.
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