How high off the water for MH bulbs?

[eww]

We just set up the temporary MH fixture and I think we may be a bit high. The bulbs are about 16" above the water surface. We intended on 12" but I forgot about the 4ish inches the bulbs are set up into the fixture. It's a 72" Hamilton 250w/400w/250w setup if it matters.

One other thing... the cooling fans in the ends of the fixture are REALLY loud, like bad bearings loud. Will it damage anything if they aren't turned on?

Any input is appreciated.

Eric

 

[akunochi]

It could damage teh fans more....11" is what i ran my lights at.

 

[eww]

Thanks Seth. Did you have them at 11" to the bulb or tot he glass on the bottom of the reflectors? The reason I ask is the fixture box on this light is 4" deep from the glass to the bulbs.

 

[Krish]

I ran my halides at 8 inches off of the water. I guess it all depends on tank depth and coral placement.

 

[returnofsid]

I run a 250 SE Hamilton pendant at 8" off the water, over a 40 breeder.

 

[mfinn]

I mounted all my mh bulbs so the bottom of the bulb was at 9" from the water.

Can you get to the center of the fans where the shaft is?
Maybe a little drop of 3-in-1 oil.
Or if it has a separate 12 volt power supply, maybe a lower wattage one?
I turned my power supply to the fans on my T5 fixture down to a lower setting. Alot quieter and still working

 

[Krish]

I run a 250 SE Hamilton pendant at 8" off the water, over a 40 breeder.

Copycat!! :fencing:

 

[eww]

Thanks guys. I'm gonna lower then tomorrow then. I will but the glass 5" off the water so the bulbs will be 8-9". While it's out being lowered I will look at either oiling or just replacing the fans. The computer fans are cheap as long as there is a power supply in the fixture for 12v fans.

 

[Peppie]

OOOOOpppppssss!!!!!!!!

Man O Man. Becca is going to give you a black eye if you dont get this light thing figured out.

Would-a Could-a Should-a.. LMAO

 

[eww]

No problem. A little slice and dice and all will be fine. Actually this will move the light down flush with the front piano door so it will look pretty good too.

 

[user 2204]

You might be able to lube the bearings in the fans. Here's a link to a how-to, most fans bearings are acessable under the label.

Cheers,
Alex

Fan maintenance - oiling bearings for fun and profit!

 

[eww]

Thanks Alex. I will have to check that out and see what can be done. I appreciate it.

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[jrgilles]

My 2X250W MH are 6" off the water. Seems low compared to everyone else, but corals love it. My ballasts might not be the best though, so might not be getting all 250 W out of the bulbs.

As for the fans, could you position another fan to blow down the length of the fixture to keep them cool? I would be hesitant to run them without any ventilation. Could damage the bulbs (which maybe you don't care about) and the evaporation off your tank would probably get pretty high.

My fixture fan went out and I replaced it with a DC computer fan I bought at radio shack. DC fan was probably 25 bucks or something though. AC fans are much cheaper.

 

[mcoomer]

Given the low cost of computer fans I would recommend against running them, or even attempting a repair. Unlikely, but should the fan fail in a manner that allows it to continue to try and work you could end up with a fire. That would ruin your day.

Mike

 

[eww]

Thanks Mike. This is all temporary a our LEDs are on order and should be ready in 6-8 weeks.

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