Raising the roof

[von_rahvin]

I built myself a wonderful custom hood. it has fann and ever thing is integrated, however, it is too short only 8" for MH and i REally REally want o go for Metal halides. What should i do? I spent alot of time and not a little bit of money on this hood.

 

[mr . salty]

Sorry to say,But you should have spent a bit more time at the drawing board...If your inside clearance between the water and the inside of the hood is less than 12",you will need to rebuild the hood.Or forget about MH...

 

[bluegoose972]

Can you cut circular holes in the top of the canopy and mount the lights directtly to the top of the canopy? I'm thinking of the type that typically hang from the ceiling. You could then run the cord down the back of the tank to the power supply. Sure, you would see the black/white light shroud, but you would save the canopy and heck, it might not look so bad afterall.

 

[rhomer]

Hey Mr. Salty why do you say there needs to be 12 inches of clearance? I've seen many with 6 inches of clearance. Is this for his size hood?
I was planning on MH and read you need 6 inches of clearance. I planned accordingly. Am I mistaken? <img src="graemlins//confused.gif" border="0" alt="[confused]" /> <img src="graemlins//confused.gif" border="0" alt="[confused]" />

 

[mini-reefer]

Same thing here, almost. I have a set of 175 watt 12000K mh's and ballast on the way.
They are going to be put in over my Oceanic 72 bowfront. I have the canopy that came with the tank. There is exactly 8 3/8" between my water line and the bottom of the support in the middle of the canopy. After attaching the reflector to a 3/4" sheet of sealed plywood, I'm left with 7 5/8". So now I have to see how far the mogule socket will hang below that. If its about 2", then I'm left with around 5 5/8" of clearence between the bulb and the water line. So now what?
Is the clearence room suggested for evaporation and heat purposes only? If thats the case then I'll try to deal with that issue in itself. If you have seen an Oceanic bowfront canopy then you would see there are not alot of options if you want to be able to remove the canopy but not the lighting.
Anyone else have any thought on this issue?
Mini-Reefer

 

[mini-reefer]

Oh, one more thing while on the subject.
I have the glass tops for my tank as well. Do I need to use them as a form of UV protection, or can they be removed and have an open water surface below the mh's? Granted that leaves very little area between the water and hot bulbs. I guess what I'm asking is basically, Do you HAVE to have a UV filter(glass/acrylic)for mh's?
Mini-Reefer

 

[mr . salty]

The thing I don't think you are taking into account here is #1, the diameter of the bulb.Most MH bulbs are around three inches in diameter...#2 mounting this bulb to allow clearance from the canopy...This leaves a minimum of about 5" to the center of the bulb.Now add the diameter,you are up to 6-7 inches...Then you need at least two or three inches between the bulb and the water.Now you are up to 10inches....Some bulbs do have a smaller diameter,like the Blueline bulbs,but are these the bulbs you are planning on using???????Now the problem with a glass top between MH bulbs and the water is that this glass will get VERY hot...Then you end up getting a buildup of salt that gets baked on by the heat.This is a REAL PAIN to clean every other day or so...So the glass is not really a good thing...

 

[mini-reefer]

Ok. So no glass tops once the halides are up and running. So do you need any sort of UV protection in between the bulb and water or can you go protection free?
Mini-Reefer

 

[mr . salty]

I have never had anything between the bulb abd the water...

 

[mini-reefer]

Thats what I thought. But, this is my first set of metal halides so I wanted to be sure. Thanks alot for your help!
Mini-Reefer