MH, How much Clearance?

bunzaroo · 07/20/2008, 10:10 AM

I am going to ditch my PC's for a MH's undercanopy setup. What is the minimum clearance that everyone recommends, fan placement? Thanks

Sk8r · 07/20/2008, 10:12 AM

9 inches from water surface is a good distance. You DO want a glass shield between MH and water splash, plus cooling fan at either end is a good idea.

bunzaroo · 07/20/2008, 10:24 AM

How should I direct the fan , at the water surface or at the actual lights, sorry Rookie here!!

Sk8r · 07/20/2008, 11:18 AM

At the lights. The glass shield stays cool enough to touch, thanks to the fans. On my bought-fixture, two standard good computer fans, one blowing in directly onto the bulb, one exhausting out at the other end, which also helps a bit with the dust problem. They're wired to go constantly: they could be wired to go whenever the lights go on.

And I can't overemphasize how important that tempered glass shield is: the mh lights are like movie projector bulbs---you want not to get your fingerprints on them: handle them with tissue or the like; and a splash of water hitting one when it's on will shatter it.

Nuuze · 07/20/2008, 11:31 AM

9-12 inches is good distance. Point the fan to blow between tank and lights to circulate the heat.

Be aware you will have more water evaporation.

bunzaroo · 07/20/2008, 11:56 AM

How should I direct the fan , at the water surface or at the actual lights, sorry Rookie here!!

che25 · 07/20/2008, 12:50 PM

I keep mine at about 8.5" above the water. The fans are installed with the fixture. I'm using the following setup:

http://www.marinedepot.com/ps_ViewIt...s~vendor~.html

ahullsb · 07/20/2008, 01:18 PM

I agree with the height stated above. Keep that fan pointed right at the lights. I used an infrared thermometer on my glass shield and the temp was over 200 degrees! Sk8r is lucky, I burn my arm on it occasionally.

07/20/2008, 10:10 AM	#1
bunzaroo Registered Member Join Date: May 2008 Location: Miami,FL Posts: 617	MH, How much Clearance? I am going to ditch my PC's for a MH's undercanopy setup. What is the minimum clearance that everyone recommends, fan placement? Thanks

07/20/2008, 10:12 AM	#2
Sk8r RC Mod Join Date: Feb 2006 Location: Spokane WA Posts: 34,628 Blog Entries: 55	9 inches from water surface is a good distance. You DO want a glass shield between MH and water splash, plus cooling fan at either end is a good idea. __________________ Sk8r Salinity 1.024-6; alkalinity 8.3-9.3 on KH scale; calcium 420; magnesium 1300, temp 78-80, nitrate .2. Ammonia 0. No filters: lps tank. Alk and cal won't rise if mg is low. Current Tank Info: 105g AquaVim wedge, yellow tang, sailfin blenny,royal gramma, ocellaris clown pair, yellow watchman, 100 microceriths, 25 tiny hermits, a 4" conch, 1" nassarius, recovering from 2 year hiatus with daily water change of 10%.

07/20/2008, 11:18 AM	#4
Sk8r RC Mod Join Date: Feb 2006 Location: Spokane WA Posts: 34,628 Blog Entries: 55	At the lights. The glass shield stays cool enough to touch, thanks to the fans. On my bought-fixture, two standard good computer fans, one blowing in directly onto the bulb, one exhausting out at the other end, which also helps a bit with the dust problem. They're wired to go constantly: they could be wired to go whenever the lights go on. And I can't overemphasize how important that tempered glass shield is: the mh lights are like movie projector bulbs---you want not to get your fingerprints on them: handle them with tissue or the like; and a splash of water hitting one when it's on will shatter it. __________________ Sk8r Salinity 1.024-6; alkalinity 8.3-9.3 on KH scale; calcium 420; magnesium 1300, temp 78-80, nitrate .2. Ammonia 0. No filters: lps tank. Alk and cal won't rise if mg is low. Current Tank Info: 105g AquaVim wedge, yellow tang, sailfin blenny,royal gramma, ocellaris clown pair, yellow watchman, 100 microceriths, 25 tiny hermits, a 4" conch, 1" nassarius, recovering from 2 year hiatus with daily water change of 10%.

07/20/2008, 12:50 PM	#7
che25 Registered Member Join Date: Jun 2008 Location: San Francisco, CA Posts: 173	I keep mine at about 8.5" above the water. The fans are installed with the fixture. I'm using the following setup: http://www.marinedepot.com/ps_ViewIt...s~vendor~.html __________________ Ave caesar! Morituri te salutamus Current Tank Info: 75 gal. glass, mixed reef/fish(SPS, LPS and softies), 2X150 MH w/130 watt actinic, Euro Reef RS80 Skimmer. DIY ATO w/Kalkwasser and 10 gal. DIY Fudge. DIY RODI system.

07/20/2008, 01:18 PM	#8
ahullsb Registered Member Join Date: Sep 2006 Location: sacramento, ca Posts: 2,729	I agree with the height stated above. Keep that fan pointed right at the lights. I used an infrared thermometer on my glass shield and the temp was over 200 degrees! Sk8r is lucky, I burn my arm on it occasionally. __________________ Andy Sacramento, CA Current Tank Info: 55 gallon reef w/20 gallon sump/ER135/ 75 pounds of live rock, 4 in sandbed, 2 b&w ocellaris clowns, yellow watchman/pistol, rosy scaled wrasse, Mystery wrasse, Copperbanded Butterfly, Lighting 48" outer orbit 2 150 mh/ 4 t5 actinics

07/20/2008, 10:24 AM	#3
bunzaroo Registered Member Join Date: May 2008 Location: Miami,FL Posts: 617	How should I direct the fan , at the water surface or at the actual lights, sorry Rookie here!!

07/20/2008, 11:31 AM	#5
Nuuze Registered Member Join Date: Sep 2000 Location: NorCal, California Posts: 3,550	9-12 inches is good distance. Point the fan to blow between tank and lights to circulate the heat. Be aware you will have more water evaporation.

07/20/2008, 11:56 AM	#6
bunzaroo Registered Member Join Date: May 2008 Location: Miami,FL Posts: 617	How should I direct the fan , at the water surface or at the actual lights, sorry Rookie here!!