# DIY 980 Watt MH/T-5 VHO Fixture



## travis (Oct 5, 2004)

I just got finished building a new light fixture for my 125G tank and thought I would post some pictures and details of the unit. Specs are:

*Fixture
*
72"x17" (suspended above open-topped 125G tank)

*Lamps

*2 x 250w MH 10000K
8 x 60w 36" T-5 VHO (2 x Giesemann 6000K Midday, 2 x Giesemann Pure Actinic)

*Ballasts*

2 x ARO 250w Electronic MH Ballast
1 x Icecap 660 T-5 Ballast (Driving four 39w T-5 HO lamps at 60w T-5 VHO)
4 x Advance Centium T-5 Ballast at 2x Overdrive (Each driving one 39w T-5 HO lamp at 60w T-5 VHO)

I built the fixture framework from an aluminum server rack that I was no longer using. It worked very well because it is extremely rigid and strong, yet lightweight. The lights are mounted on the framework and wired to the ballasts which are remotely mounted roughly six feet from the tank. I really like the color of the Giesemann Midday lamps and added one set of Giesemann Pure Actinics to bring out the blues and silvers of my African cichlids. Ps. demasoni really glow under good actinics.

I've been running the 250w MH fixtures with 4 x 39w T-5 HO lamps over my 125G for about a year now with great results - colors are astounding and density of growth is excellent. Increasing the light intensity will, of course, make it more difficult to keep the tank in balance, but I am confident that my dosing regimen is adequate and am anxious to find out what sort of results I will get with almost 8 wpg over such a large tank. The MH light will only be run for two to four hours during the height of the photoperiod and the T-5s will be staged to simulate the passing of the sun from the front to the back of the tank. I'll post some pictures of the tank with the lights mounted when I get a chance.

Top-down shot of fixture with ballasts:










Fixture with lamps installed, ready for first test:










First light:










At full brightness:


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## intermediate_noob (Oct 18, 2007)

BRILLIANT (no pun intended) idea to use the server rack as a fixture!! How are you going to enclose each?

Also, what model of Advance ballast did you use? Thanks again for sharing!

- Chris


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## Squawkbert (Jan 3, 2007)

Looks nice - if only your 125g were ~2' deeper...


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## Brilliant (Jun 25, 2006)

Thats lookin nice. When I saw it I was thinking you could contruct this with metal wall studs.

I thought VHO was variable high output. Learn something new everyday.

I have a question. Can you tell me the dimensions of the waterproof endcap?I would like to know how much clearance I need to mount in a fixture. Sorry IceCap's spec sheet isnt legible and sunlight never answered my email.


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## gibmaker (Jan 3, 2007)

Looks awesome.......980 watts, don't burn your house down.


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## taekwondodo (Dec 14, 2005)

With the MHs you will get better coverage if you rotate the reflectors 90o. Right now, they are reflecting most of their light front-back and you will wind up with some issues with dark areas in the tank in the center and at the edges (which might not be obvious because of the T5HOs). Just a suggestion (the guys on reef-central recommend this, as does hellolights).

I just recently went from 2 175s SEs to three 150 DEs and the difference was night-and-day.

and...

DUDE - THATS A LOT OF FRIGGEN LIGHT!!!


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## travis (Oct 5, 2004)

> How are you going to enclose each?
> 
> Also, what model of Advance ballast did you use?


Currently the fixture is open, no enclosure. I've considered fabricating a carbon fiber shell for it because of weight issues with a hanging fixture and the fact that I don't have access to a metal shop. I'm also a big fan of the way carbon fiber looks.

The model of ballast I used was the Advance ICN-2S54. I will eventually replace them with another Icecap 660 to reduce clutter and because the Icecap is just a technically superior piece of equipment.



> Looks nice - if only your 125g were ~2' deeper...


lol - Well I am planning on replacing it with a 180 or possibly larger tank this summer. I'm sure it will do the job regardless of what I end up going with



> Can you tell me the dimensions of the waterproof endcap?


The endcaps (with standoffs) are 2 3/4" in height and 2 1/2" in length and width, so you will need about 3" of headroom to comfortably mount them in a fixture or canopy.


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## intermediate_noob (Oct 18, 2007)

Thanks for the info, and let me just say again, WOW. 

Do you have reflectors on the T5s?


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## Brilliant (Jun 25, 2006)

Thanks man! 

Oh yeah good job recycling the rack. Keep up the good work I cannot wait to see the final project. The sticker shock from wpg folks is funny


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## travis (Oct 5, 2004)

> With the MHs you will get better coverage if you rotate the reflectors 90o. Right now, they are reflecting most of their light front-back and you will wind up with some issues with dark areas in the tank in the center and at the edges (which might not be obvious because of the T5HOs). Just a suggestion (the guys on reef-central recommend this, as does hellolights).


Thanks. I'll try rotating the MH reflectors to see what kind of difference it makes. I would never have thought of that.



> Do you have reflectors on the T5s?


Yes. I'm using Icecap's parabolic clip-on reflectors. They are definitely the way to go vs. a single large reflector for all bulbs - a massive improvement in light intensity.


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## emhigginson (Mar 27, 2008)

Now that you've had these lights going for a month, how do you feel about having almost 10w/g. Do you have to trim your plants daily or hourly?


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## hoppycalif (Apr 7, 2005)

The reason we haven't heard from him lately is that the whole house is now overrun with the plants! Or else, he lost his sun glasses.


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## curt_914 (Sep 28, 2007)

Travis hows this fixture working for you?? You got me thinking about just building my hood now!! And I am seriously considering the 48" Icecap conversion kit for an old black acrylic hood I have.

Curt


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## reybie (Jul 18, 2007)

LOL, I can see Jumanji


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## travis (Oct 5, 2004)

Sorry for not updating. I've been running the lights for about two months now and can say that one must learn restraint when having this much wattage available. I start off with only two of the eight T-5s in the morning and slowly work my up to all eight. Then the MH lamps kick on for about three hours. The T-5s then step back down until only the two actinics are running (for a dusk-like effect). 

When I first set the fixture up I was running all of the T-5s for a total of nine hours (with MH lamps on for four hours in the middle of this period), but have since backed down to seven hours (T-5) and three hours (MH) after running into some hair algae issues that cropped up even with ideal NO3 and PO4 levels. I think I have things dialed-in now and plant growth is phenomenal. Some of my Limnophila grows over an inch a day and many of the stems require at least weekly trimming. And my African cichlids take a siesta while the MH lights are on


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