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scubadude

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My question is directly related to the 250watt HQI bulbs, Im in the process of building my 220gal Reef tank (72"x24"x30") which will be mostly SPS, and some softies, and LPS in there too. I am gonna build my own lighting system which will house 3 maybe 4 of the 250 HQI bulbs, as I have read Sanjay Joshi's report and love the par and spectrum that they emit, However what concerns me is the UV rays that these lights emit. My tank will be in my Office about 2' away from where I sit for 10hrs a day 6 days a week, and I dont want to have Skin Cancer after 6 mos
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I have talked with numerous glass shops and have read an indepth thread at ReefCentral about these DIY HQI lamps, As the glass shielding is what it all boils down to....What type of glass, and how thick should it be. There are a few things relative here from what I see....Heat, UV rays good to corals (SPS), UV rays bad to corals, and color spectrum. Most of the guys that have replied to this thread on ReefCentral seem to think that 1/4 tempered glass should be fine for shielding the UV rays enough to not cause damage, however talking to many glass experts in the past few days they have told me that regular 1/4" tempered glass does NOT shield that much of the U/V rays. I want the best of both worlds. I want to give my corals all that they need/want from these lights, and at the same time block out what can damage the corals and/or me. I have been told that their is 3 different types of UV A, B, and C. Which ones are good and which are bad? Or have I been misled? As far as glass goes its Measured In SHGC (Solar Heat Gain Coefficient) The higher the SHGC the more U/V will pass through it. There is also VT (Visual Transmittance) Which from the way the Glass experts explained it to me that the Higher the VT the Less par goes through the glass. This is all speculation on my behalf, I am by NO means a glass or light physics expert. My Glass man has told me that if I can tell him exactly which UV's I want to block and Which I dont want to block then he can probably supply the correct glass, now the other thing that he has told me is opaque tinting or filming layers in certain types of glass will block UV rays I.E.: a clear piece doesnt block much UV's, a slight opaque blue will block some UVs, and a slight blue green will block even more, and a green will block even more than the blue green etc etc. This particular glass he was discussing is called Low E glass and is made with a Pyrolitic coat as well as a Monolithic coat. My thoughts where that a shade of blue or even blue green may accomplish that "Perfect Coloring" effect and at the same time elliminating our harmful UV's ? here again this is all speculation....tell me what you think.

Here is the thread that most of this evolved around

http://www.reefcentral.com/vbulletin/showthread.php?threadid=32376

Warning: The thread is about 8 pages long
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Any input you can give me would be greatly appreciated! If you feel up to it then you can just email me or just post your response right onto the thread.
 

Roadtoad

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1/4 inch glass should do the trick especially if the light has to travel through the water and tank glass before it hits you. You can get special UV absorbing glass-talk to a specialty shop (borosilicate?). I was thinking of making one of these fixtures and I thought a glass tube around the bulb would be a good way to go. I should test this borosilicate idea.
 

jerryreef

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I have also been following that thread at www.reefcentral.com, as I am in the midst of construction the canopy for my 180-gallon tank. And, Sanjay Joshi's comments did cause some reservations with double ended HQI lamps.

I am very much concerned about excessive uv radiation and possible damage to livestock, considering that recently my dog was put down due to cancer. In any event, Cyro manufactures acrylic products that affords UV filtering

I thought you might be interested that they have two types of sheets, ACRYLITE FF OP-3 and OP2.

OP-3 filters goes into the 400 nm range , in which case it also blocks out the blue light, as it has a slight yellow tint. OP-3 is often used in museums to protect paintings and it utilizes the extrusion process.

OP-2, however, only filters out, up to the 390 nm uv range, in which case the acrylic is clear. Furthermore, being that it is “cell cast” it’s application is more as protective cases/containers in museums. Being manufactured with the “cell cast” technique, it does not distort images placed at a distance, which IMO is most suitable for aquariums.

Still trying to figure out the optimum lighting for my reef tank.

[ October 06, 2001: Message edited by: jerryreef ]
 

scubadude

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The hard part about it is Heat...you are gonna need something thick enough and strong (tempered) enough to withstand the heat....these bulbs produce almost 3000 Deg F at the envelope and you are NOT supposed to blow air directly on the bulbs!! So this can be tricky....but i think the answer could be as simple as 1/4" tempered glass shield and plenty of venting and fans just under the shield to cool it!
 

jerryreef

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Whoa-o-oh-oh-o.................that is hot……in that case you’d better settle for thick tempered glass. What is the distance of the lamps from the water surface and, how do you plan to cool the heat generated within the canopy? Are there HQI lamps designed using hard glass envelope?
 

bsme

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Noticed that Custom Aquatic carries replacement lens for the AB Starlight/Spacelight HQI fixtures. Have to look hard for them. Cheap price but I'm not familiar with size of lens used. I assume its OEM for those worried about UV shielding.
 

Carpentersreef

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How about ordering the glass directly from Aqualine? Be patient, though. I ordered my 3 x 250W HQI Aquaspacelight from them, and it took 6 months (re CSI Electrical approval) to get here. The glass alone should be a lot quicker.

Mitch
 

jerryreef

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<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote
Noticed that Custom Aquatic carries replacement lens for the AB Starlight/Spacelight HQI fixtures

The only issue that I have with the spacelight is that it is limited to a 5-1/8" width. I would have preferred a width of at the least 14" wide.

Getting your own tempered glass cut to size would still be the DIY best option.
 

scubadude

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Here is what I have come up with so far

I have 3 250w HQI Double Ended bulbs in a hood with a DIY reflector made from a storm panel (aluminum) and aluminum flashing all bent and cut to my specifications
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The reflector is 54" x 16" and there is a 1/4" piece of standard tempered glass about 2" underneath the reflector The glass is 56" x 22" and cost me about $40 the bulbs are about 4" away from the glass, and the glass is about 5" away from the water line. The hood is NOT totally enclosed for ventilation purposes. Please note that Im still in the "Trial" phases on this lighting system and am open to critique and opinions. Heres some pics.


hqi1.jpg


hqi2.jpg


HQIa1.jpg


HQIa2.jpg


HQIa3.jpg


HQIa4.jpg
 

Timbo1

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I was under the impression that double ended bulbs had to be kept within an enclosed, un ventilated enclosures because they have an optimum operating temperature that must be maintained for longest life and best color.

Anyone else know if this is true?

Tim
 

scubadude

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Yes, I researched and found out basically what Jerry just posted....There is VERY little ventilation for the bulbs in the reflector. I have 2 RS 4" fans that are on top of the hood drawing air out of the canopy but the air drawn out is between the reflector and the canopy NOT inside the reflector where the bulbs are.
 

jerryreef

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Yeah Tim, Halogen Quartz Iodide (HQI) lamps need to burn at temperatures of over 1000ºF/537ºC for proper operation. These lamp filaments can heat up anywhere between 3000°F/1649°C and 5000°F/2760°C.

At those temperatures the glass surrounding the filaments must maintain a temperature of more than 482ºF/250°C, or else condensation will occur.

That's also the reason for the Quartz glass, the high temperatures.

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr> <a href="http://www.bytecraftentertainment.com/halogentheory.phtml" target="_blank"> The operating temperatures for iodine and iodine compounds, to run a successful regenerative cycle requires a filament temperature of 1700ºC with the bulb wall at least 250ºC. The quantity of iodine required is variable and dependent on the amount of tungsten to be regenerated, this in turn being related to the filament temperature and overall lamp load.

The greater the proportion on iodine vapour in the lamp, the greater is the light loss due to absorption by the characteristic pink vapour; up to 5% in practical lamp designs.
</a> <hr></blockquote>

Jerry

[ October 23, 2001: Message edited by: jerryreef ]</p>
 

jerryreef

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scubadude, have you seen David's 400watts 20000K MH lamps that's in his main show tank?

Since I've already ordered for 3 x 250watt 10000K double-ended HQI lamps; I should have enough space to add in 2 x 400 watts 20000 GE USIHO. The only thing is that it'll get a little troublesome to install uv glass over the double-ended and leaving it bare for the Radium lamps.

Jerry

[ October 25, 2001: Message edited by: jerryreef ]</p>
 

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