MH and UV

erc111 · 08/15/2006, 09:40 PM

Posted this on reefkeeping with no response, I'll try here.

OK, after reading this link.

http://www.masla.com/reef/uvlighting.html.

I am wondering what everyone does.

I am thinking I should get some Lexan Solar for my 2 250W SE 10k MH and 2 96W PC 03s.

I have been happy with the colors and although I haven't seen much growth, my oldest sps is only 4 months.

My lps, zoas and shrooms are growing like crazy.

What do y'all think.

MH UV=bad and needs to be shielded or not.

Travis L. Stevens · 08/16/2006, 07:29 AM

Well, for starters, your link doesn't work

Secondly, Single Ended metal halides give off little UV-A or B or C (I think it's UV-C) light that is harmful. The glass tube that the halide is built into acts as the UV Shield. Now, the Double Ended metal halides is a whole other story. They need the UV Shield. You'll even kill your corals if you don't have something over it.

erc111 · 08/16/2006, 08:15 AM

Sorry about the link. Maybe this one will work.

http://www.aquarium-design.com/reef/uvlighting.html

The jist of it is that even with the glass envelope on SE bulbs there is STILL a substancial amount of UV_A, B & C that are emitted.

cabin · 12/29/2006, 05:09 AM

I recently put a SE 250 watt metal halide retrokit lamp on one side of my aquarium, and a 250 watt DE Aqua Medic luminaire on the other side. I've had great difficulty with growing macro algae on the side with the retrokit lamp--it becomes very pale after placing in on the bottom of the tank on that side. Being a kit, this lamp has no glass shield, and I accepted the common wisdom that single-end lamps are already shielded for UV by the glass envelope. After reading the interesting article posted by erc111, however, I'm wondering if adding a Lexan or similar material shield under that lamp would solve my problems with growing macros and seagrass. At the very least, I would be less worried about my eyes when I work around the tank. I think this is an important article and I wish more people would comment on it.
Wynne

Driftwood · 12/29/2006, 09:05 AM

I worry a little when I see light coming out of the side vents of my aqua medic fixture...

Very interesting article, lexan solar might be the way to go!

erc111 · 12/29/2006, 10:25 AM

Cabin,

Thanks for bringing this up again.

I, too, would like to hear other opinions.

I have not put lexan on my tank, but still wonder if I should.

Especially since I am going to add another 250w to the 500w of SE MH on there now.

run4cvr · 12/29/2006, 10:30 AM

I was wondering the same thing recently while working on a new lighting project.

Will normal plate (green) glass work as a UV shield?

erc111 · 12/29/2006, 12:50 PM

I don't remember.
I posted this 4 months ago.
Try the link.

boxfishpooalot · 12/29/2006, 04:26 PM

Quote:

Originally posted by run4cvr
I was wondering the same thing recently while working on a new lighting project.

Will normal plate (green) glass work as a UV shield?

No it says normal glass and acrylic transmit uv light easily.

You need special uv protection glass.

pjf · 12/30/2006, 11:27 PM

Even shielded DE lamps emit a lot of UV. Take a look at Dr. Joshi's spectral plots of shielded 250w DE lamps: http://www.advancedaquarist.com/issu...4/feature1.htm.

It looks like the UV shields only block ~30% of the UV. There is more ultraviolet than red or orange in the spectral analyses. In fact, there is a significant UVA peak at 360nm. This is true virtually across the board.

If manufacturers don't improve the quality of the UV shields used, I may go to LED lighting.

08/15/2006, 09:40 PM	#1
erc111 Moved On Join Date: Aug 2003 Location: Florida Posts: 245	MH and UV Posted this on reefkeeping with no response, I'll try here. OK, after reading this link. http://www.masla.com/reef/uvlighting.html. I am wondering what everyone does. I am thinking I should get some Lexan Solar for my 2 250W SE 10k MH and 2 96W PC 03s. I have been happy with the colors and although I haven't seen much growth, my oldest sps is only 4 months. My lps, zoas and shrooms are growing like crazy. What do y'all think. MH UV=bad and needs to be shielded or not.

08/16/2006, 07:29 AM	#2
Travis L. Stevens Registered Member Join Date: Nov 2004 Location: Perry, OK Posts: 13,946	Well, for starters, your link doesn't work Secondly, Single Ended metal halides give off little UV-A or B or C (I think it's UV-C) light that is harmful. The glass tube that the halide is built into acts as the UV Shield. Now, the Double Ended metal halides is a whole other story. They need the UV Shield. You'll even kill your corals if you don't have something over it. __________________ Travis Stevens Current Tank Info: Restarting 28g Bowfront

12/30/2006, 11:27 PM	#10
pjf Premium Member Join Date: May 2005 Location: Colorado Posts: 2,954	UV through Shields Even shielded DE lamps emit a lot of UV. Take a look at Dr. Joshi's spectral plots of shielded 250w DE lamps: http://www.advancedaquarist.com/issu...4/feature1.htm. It looks like the UV shields only block ~30% of the UV. There is more ultraviolet than red or orange in the spectral analyses. In fact, there is a significant UVA peak at 360nm. This is true virtually across the board. If manufacturers don't improve the quality of the UV shields used, I may go to LED lighting.

08/16/2006, 08:15 AM	#3
erc111 Moved On Join Date: Aug 2003 Location: Florida Posts: 245	Sorry about the link. Maybe this one will work. http://www.aquarium-design.com/reef/uvlighting.html The jist of it is that even with the glass envelope on SE bulbs there is STILL a substancial amount of UV_A, B & C that are emitted.

12/29/2006, 05:09 AM	#4
cabin Premium Member Join Date: Apr 2004 Location: Maine Posts: 354	I recently put a SE 250 watt metal halide retrokit lamp on one side of my aquarium, and a 250 watt DE Aqua Medic luminaire on the other side. I've had great difficulty with growing macro algae on the side with the retrokit lamp--it becomes very pale after placing in on the bottom of the tank on that side. Being a kit, this lamp has no glass shield, and I accepted the common wisdom that single-end lamps are already shielded for UV by the glass envelope. After reading the interesting article posted by erc111, however, I'm wondering if adding a Lexan or similar material shield under that lamp would solve my problems with growing macros and seagrass. At the very least, I would be less worried about my eyes when I work around the tank. I think this is an important article and I wish more people would comment on it. Wynne

12/29/2006, 09:05 AM	#5
Driftwood Registered Member Join Date: Jan 2006 Location: Gardiner, ME Posts: 841	I worry a little when I see light coming out of the side vents of my aqua medic fixture... Very interesting article, lexan solar might be the way to go!

12/29/2006, 10:25 AM	#6
erc111 Moved On Join Date: Aug 2003 Location: Florida Posts: 245	Cabin, Thanks for bringing this up again. I, too, would like to hear other opinions. I have not put lexan on my tank, but still wonder if I should. Especially since I am going to add another 250w to the 500w of SE MH on there now.

12/29/2006, 10:30 AM	#7
run4cvr Registered Member Join Date: Jan 2006 Location: N Phoenix Posts: 99	I was wondering the same thing recently while working on a new lighting project. Will normal plate (green) glass work as a UV shield?

12/29/2006, 12:50 PM	#8
erc111 Moved On Join Date: Aug 2003 Location: Florida Posts: 245	I don't remember. I posted this 4 months ago. Try the link.