Suggestions on DIY MH Light fixture.

[Tampico]

I just finished building my DIY dual 250MH light for my 75gal tank. I had 2 M58 Ballasts and built a frame for the mogels and reflectors I ordered out of Bosch Alumn. Today I recieved my bulbs. 10k 250w Ushio MH bulbs. All 4 bulbs I recieved have a little black burns just inside of the tube near the mogel base. I look on their website to see if this is normal and see a shock. "To prevent UV burns, bulbs should be in a uv protected enclosure."

I have seen many DIY MH fixtures like the one I built. Did I buy the wrong bulbs, or should I try to enclose my fixture.

BTW the black is caused in the manufacturing and not a issue. Also tested all 4 bulbs and they work fine. and I did not get any UV burn during testing...

Any thoughts ?

[ratimpulse]

UV burn will happen over time. If i am right dont quote me on this a double ended HQI doesnt emit UV rays that it can hurt you. But a mogel style needs tempered glass to keep UV rays to hurt you. I would reccomend adding a piece of tempered glass just in case. Better to be safe then sorry in the long run when something as simple asa $20 glass may save you from a couple $1000 in medical bills.

[cccapt]

A mogul base bulb is basically a double ended bulb enclosed in a UV protected case. You do not need any additional uv protection with a single ended mogul base bulb, but you DO need a UV sheild when using a double ended bulb.

[sales weasel]

I agree with cccapt. I did a lot of reading before buying my pair of mogul based MH lights.

[ratimpulse]

Yea, got those confused sorry about that.

[Tampico]

These are single end mogel bulbs and I had thought the same thing. I had read an article about gym lights that were defective and the outer bulb cracked. Thus releasing UV into the stands. Could not find that article again today but I believe that the bulbs still lit with the outer casing cracked. It just made my head spin when I saw the section on the bulb manufacturer website about UV glass enclosures and wanted to double check.


Ushio Safety (http://www.ushio.com/support_lampsafety.htm)


will take some pics of my fixture tomorrow, I was so proud of this DIY project before I read this.

[Tampico]

Hmmmm I am truely amazed that I have not gotten scolded for breaking a cardinal rule here on RC DIY section. Due to guilty feelings, I have finally gotten around to making things right. What good is a DIY post without........................................................................Pictures!

http://i41.photobucket.com/albums/e269/Tampico1996/p1010304.jpg


http://i41.photobucket.com/albums/e269/Tampico1996/P1010306.jpg

Frame construction is Bosch Extruded Alumn. and recycled reflectors and mogels from commercial grade exterior lights. (not sure how the offcenter reflectors will work. I made my hood 6 inches deeper than the tank in order to help hide all of the plumbing, so in theory these reflectors should be perfect. Time will tell. Also may redo the mogel placement. I did not expect the Ushio bulbs to be shaped like this. Guess I have changed too many parking lot lights and expected much larger bulbs. Fram also has eyelets so I can adjust the fixture height as the bulbs mature.. Good DIY? any comments? Also I am not sure how much distance can be between the bulbs and ballasts. If possible I would like to place the ballasts in the basement below the tank on my first floor. (Magnetic ballasts and think the buzz may become annoying) Anybody know if there is a max distance for the wiring between bulb and ballast?

[Fast Fred]

Very nice, clean looking DIY project!

[RichConley]

Just a note: You're going to lose a LOT of light from those reflectors. MH bulbs put off a good amount of light towards the ends of the bulbs, and none of that is reflected down with your reflectors. You may want to line the inside of the rest of the hood with something reflective (mylar?)

[Tampico]

Coated the interior of my hood with High Gloss/High heat white spray. May need to buy some new reflectors if these do not work out. Only thing in this lighting project that cost me money was the 2 ushio 10ks. Rest of the parts were assembled from various scrap piles around work. (I have a bad habit of hiding usable items about the building.)

Here is pre paint/stain phot of the cabinet that this will hang in. Need to get some picks of it now that it is mostly finished. Still need to finish the doors.

http://i48.photobucket.com/albums/f223/Tampico96/P1010282.jpg