HQI fixture: How close to the water can I put it?

bureau13

New member
Well, I finally hung my Aqua Medic OceanLight (4x250W HQI + T5 supplemental). They suggest 6-12" over the water (my tank is acrylic for what its worth). The thing is, my tank is 36" deep, and I was borderline on whether I needed to go with 400W lamps. I ultimately decided on the 250W HQI but I want to maximize the light I do have, without causing problems.

Right now, I have them at about 11.5" over the water and on a reduced photo period so I don't shock the corals. I want to lower it though, both to get more light down to the lower regions of the tank, and because at that height its a bit too easy to see the lamps suspended above the tank....I'd prefer to NOT be able to have a direct line of sight from all over the room. I was thinking I would go down to the minimum recommended 6" but I thought I'd get feedback first...I don't want to melt my top center section, etc.

Thanks,
jds
 

Don Berry

New member
You do have to be careful in regards to center braces and metal halides. I have had an AGA center brace break on me over time due to MH heat. If you center braces is pretty thick I wouldn't worry, but otherwise it's something to think about. I doubt a couple inches is going to make the difference on any potential problems. I have my lights at 8 inches and the problem. The biggest thing to worry about in regards to HQI and lowering it would be a splash on the UV glass. I've seen them shatter before because of a splash. Once this happens your corals are in serious trouble unless you catch it quick.
 

bureau13

New member
Actually its not really a brace on my tank...its more like the part of the top that's not cut out (there are two large openings in my tank, so I think of the center part which is not open as a "brace." In reality, its just part of the tank.

Good point about the splashing...I don't seem to be getting much, but I guess it would take one overly-exuberant fish and that would be it. I'll have to see what it looks like at 8" maybe that will be low enough.

jds
 

VSpeck

Slash Smack Talker
i have mine 6" off the water (2 250w hqi on a 75gal) and i dont get too much splashing and no broken glass. the same lights were on a buddy's 330gal acrilic tank and melted the top panel on the tank at the same height.
 
Top