MH Hood Issues

[parkavenuereef]

I built my MH hood this weekend using 1 250 Hamilton 14k bulb.. soon to be 2 250W bulbs after this weekend. Anyways, I have a problem where my room seems to be getting more of the light than my tank does. the hood is 8 inches tall by 36 long. The bulb is right towards the bottom of the hood. If I lay down on my couch i am blinded by the light. the hood is about 4 inches off the top. The inside is lined with mirror glass... If anyone has any thought on the build that would be helpful.. Seems like the light is not as bright as it should in the tank...

[Gary Majchrzak]

I'm not a pro hood builder, but I know a few basic things on the subject.
You'll want to have the MH lamps mounted closer to the top of your hood (especially if it's an "open" type) and spend the bux for some appropriate reflector material.

[smoknreefrs]

Originally posted by Gary Majchrzak
I'm not a pro hood builder, but I know a few basic things on the subject.
You'll want to have the MH lamps mounted closer to the top of your hood (especially if it's an "open" type) and spend the bux for some appropriate reflector material.
thats it in a nut shell....

[Gary Majchrzak]

Here's a related thread that makes for interesting reading on the subject:

http://archive.reefcentral.com/forums/showthread.php?s=&threadid=602711&highlight=building+a+hood

[parkavenuereef]

So I should mount the bulbs towards the top of the unit. Is the glass mirror not a good idea for reflector material??

[jcanute]

thanks gary this is next on my list after plumbing.

[Gary Majchrzak]

Reflector material is VERY important. Glass mirror is not a good choice for reflector.

[smoknreefrs]

Originally posted by parkavenuereef
So I should mount the bulbs towards the top of the unit. Is the glass mirror not a good idea for reflector material??
bad idea

[parkavenuereef]

What makes the glass mirror a bad idea?? Is it due to heat and cracking issues? Or due to some other reason... Just want to figure it out so i can reason myself to trash $30 in mirror custom cut is all.. Thanks for all the advice so far guys!!

[Jedistphn]

The answer to the mirror question is yes, once you raise those MH up to the top of the canopy, heat is going to cause those mirrors to possibly crack.
Also, the light reflectivity is not "directed" which is why you are getting the light"bleed off".
A proper reflective material, (aluminum, etc..) will be able to bend, and direct the light in to the tank, thus providing more in tank light.

Hope that helps.

Jedi

[drtango]

Everything you need to know and more regarding reflectors--agree that a decent (and not expensive) parabolic reflector is key. Why spend all that money on lamps, ballasts and kilowatts and not have it hit your corals?

http://www.advancedaquarist.com/issues/mar2003/feature.htm

http://www.advancedaquarist.com/issues/mar2004/feature.htm

John

[parkavenuereef]

Ok, so here is my questions... From reading all of this, the proper shape for the reflectot is " v " shaped then correct?? As far as aluminum, I have duct aluminum, not reflective at all obviously.... where can I get this polished stuff locally??

[drtango]

I'm pretty sure the polished stuff is hard to come by, as are the tools to properly work the material--

These work fine, there's plenty of other options out there...

http://www.hellolights.com/methalparref.html

[parkavenuereef]

Done, I think a pair of those is best... I am adding a set of 96W pc's tonight as a add on... Good idea or bad?

[drtango]

PC's are a fair idea IMO--give out decent light but need a reflector as opposed to VHO which have an "internal" reflector.

Maybe leave your mirror in there, mount the parabolics on the mirror with a 1/4 inch standoff so it won't get so hot, and mount the PC's to the mirror?

You'll be amazed how much more light is directed into the tank with the parabolics.

John

[CountersCC]

Hey whats up, Reflector is the way to go

[parkavenuereef]

CountersCC, Reflectors is the way to go... Went to the LFS tonight, checked out a reflector... seems to be what i need...