distance of halide from water

oscarslr · 12/09/2008, 09:43 PM

30 inch tall tank with 250w halides what distance should i place the halides from the water

reefnetworth · 12/09/2008, 09:49 PM

appx. 8"-10" is typical. 250W, i would start at ten, and monitor your temp. for about a week, if its stable, leave it at 10".
plus, at 10" you will get a broader spectrum of light.

reefworm · 12/10/2008, 12:17 AM

agreed. mine's just over 9" above the water over a 29 gal. temp is not a problem - open top and cooling fan blowing over the surface and timed with the light.

cczarnik · 12/10/2008, 05:20 PM

Reflector choice will influence this as much as wattage. Takes a lot of par to go 30", I'd go as close as possible while maintaining good light distribution.

cdentii1 · 12/10/2008, 06:16 PM

My 250W MH's are 8" the back of canopy is open with no fans, yes there is a temp increase however not drastic.

Gieser · 03/28/2009, 12:16 PM

Same question, how high for a 31", but with 400w MH and LunenMAx reflectors. I have the rack for the lighting at about 9" from the top of the tank which would be about 11" from top of water. Just curious.

ser_renely · 03/28/2009, 01:08 PM

not to hijack but what about 150w?

Delr3 · 03/28/2009, 02:14 PM

I have 3 250w MHs at 10in above the water, and I do not see much of a water temp increase, not over 1 degree in temp change. I do have 10, 4in pc fans that I wired into the hood so they pull a lot of head off that seemed to heat the tank up before I did that.

reefworm · 03/28/2009, 11:24 PM

just to get to what I suspect is part of the concern - rise in temp. as long as its within a few degrees [say 3~5] it shouldn't be a problem as the animals will acclimate to those changes as they do in the wild.

ct_vol · 03/29/2009, 05:56 AM

Quote:

Originally posted by ser_renely
not to hijack but what about 150w?

150w would not be enough for a 30" reef tank unless you only kept coral in the top 1/3 of your tank or if you wanted to go FOWLR...

reefscape15 · 03/29/2009, 06:03 AM

I think all MH lights should be 8" up at least, but i've seen them as far as 24" off the water and still perform. The air that its cutting through will only very slightly diminish your output, but as for the different wattages: 150 is best on tanks under 16" tall, 250 is best for up to 24", 400 watt is usually needed on anything deeper than 24" to be able to keep SPS at the bottom of a tank. I have a 250watt only about 5" off my water, but thats all the room i have at the moment. It does raise temp a few degrees, but it's not enough to worry me

DEERE G · 03/29/2009, 08:34 AM

I run my 250w bulbs about 9" from the water's surface.

ct_vol · 03/29/2009, 10:33 AM

Quote:

Originally posted by reefscape15
I think all MH lights should be 8" up at least, but i've seen them as far as 24" off the water and still perform. The air that its cutting through will only very slightly diminish your output, but as for the different wattages: 150 is best on tanks under 16" tall, 250 is best for up to 24", 400 watt is usually needed on anything deeper than 24" to be able to keep SPS at the bottom of a tank.

This is exactly what I would have said a year ago, however, advancements in Reflector technology have made it possible to use a 250w MH successfully on a 30" deep tank... THe Lumen Max Elites are made specifically for 30" tanks, and I've heard that Lumen Brights are comparable as well... They focus the light in a narrower beam than do LumanArcs... I have some LME's on my 150g (48x24x30) and they throw out some ridiculous PAR numbers, even at the bottom...

Without high performance reflectors, the advice given by reefscape15 is what I'd follow though...

12/09/2008, 09:43 PM	#1
oscarslr Registered Member Join Date: Jun 2007 Location: Tucson, AZ Posts: 782	distance of halide from water 30 inch tall tank with 250w halides what distance should i place the halides from the water

12/09/2008, 09:49 PM	#2
reefnetworth Premium Member Join Date: Mar 2006 Location: U.S.A. Posts: 3,810	appx. 8"-10" is typical. 250W, i would start at ten, and monitor your temp. for about a week, if its stable, leave it at 10". plus, at 10" you will get a broader spectrum of light. __________________ GIVE A MAN A FISH, YOU FEED HIM FOR A DAY. TEACH A MAN TO FISH, HE FEEDS HIMSELF FOR LIFE. (NEVER, underestimate another man's greed) Current Tank Info: SPS dominated barebottom display with BB sump since 2005, most consistant parameters in 19+ years of reefkeeping.

12/10/2008, 12:17 AM	#3
reefworm Registered Member Join Date: May 2000 Location: Waxhaw, NC USA Posts: 2,139	agreed. mine's just over 9" above the water over a 29 gal. temp is not a problem - open top and cooling fan blowing over the surface and timed with the light. __________________ "The best argument against democracy is a five-minute conversation with the average voter." - Thomas Jefferson Current Tank Info: 29 gal. reef/assist with 75 gal. at the school

03/28/2009, 01:08 PM	#7
ser_renely Registered Member Join Date: Mar 2008 Posts: 1,820	not to hijack but what about 150w? __________________ RIP: Osc. Clown - Ammonia, YW GobY - overflow, YW Goby - Pistol shrimp, Firefish - acclimation. 5 Fire fish - pistol shrimp, Mandarin - Pistol shrimp!!!!! Current Tank Info: 60g Cube, 15g sump/fuge,Tunze 9010 skimmer, Reefbreeders Photon 16" - 2 Osc. Clowns,2 Lyretail Anthias, Blue Chromis, mp20, mp10....another DAMN pistol shrimp!

03/28/2009, 02:14 PM	#8
Delr3 Registered Member Join Date: Feb 2009 Location: Idaho Posts: 60	I have 3 250w MHs at 10in above the water, and I do not see much of a water temp increase, not over 1 degree in temp change. I do have 10, 4in pc fans that I wired into the hood so they pull a lot of head off that seemed to heat the tank up before I did that. __________________ Hurry up and wait. Current Tank Info: 125 g, 3 koralia 4s, octopus nw 200, 55 g sump

12/10/2008, 05:20 PM	#4
cczarnik Registered Member Join Date: Dec 2004 Location: Franklin, TN Posts: 433	Reflector choice will influence this as much as wattage. Takes a lot of par to go 30", I'd go as close as possible while maintaining good light distribution.

12/10/2008, 06:16 PM	#5
cdentii1 Registered Member Join Date: Jun 2003 Location: Canton, OH Posts: 527	My 250W MH's are 8" the back of canopy is open with no fans, yes there is a temp increase however not drastic.

03/28/2009, 12:16 PM	#6
Gieser Registered Member Join Date: Jan 2004 Location: Memphis, TN Posts: 460	Same question, how high for a 31", but with 400w MH and LunenMAx reflectors. I have the rack for the lighting at about 9" from the top of the tank which would be about 11" from top of water. Just curious.

03/28/2009, 11:24 PM	#9
reefworm Registered Member Join Date: May 2000 Location: Waxhaw, NC USA Posts: 2,139	just to get to what I suspect is part of the concern - rise in temp. as long as its within a few degrees [say 3~5] it shouldn't be a problem as the animals will acclimate to those changes as they do in the wild. __________________ "The best argument against democracy is a five-minute conversation with the average voter." - Thomas Jefferson Current Tank Info: 29 gal. reef/assist with 75 gal. at the school

03/29/2009, 06:03 AM	#11
reefscape15 Registered Member Join Date: Jan 2009 Location: Elmira Heights, NY Posts: 2,812	I think all MH lights should be 8" up at least, but i've seen them as far as 24" off the water and still perform. The air that its cutting through will only very slightly diminish your output, but as for the different wattages: 150 is best on tanks under 16" tall, 250 is best for up to 24", 400 watt is usually needed on anything deeper than 24" to be able to keep SPS at the bottom of a tank. I have a 250watt only about 5" off my water, but thats all the room i have at the moment. It does raise temp a few degrees, but it's not enough to worry me __________________ A new beginning........... JIM Current Tank Info: 5g standard softie/zoa tank, just starting a 20H

03/29/2009, 08:34 AM	#12
DEERE G Passing Through Join Date: Jan 2008 Location: ATL Posts: 1,503	I run my 250w bulbs about 9" from the water's surface. __________________ -Keith- Current Tank Info: DRY