proper hqi placement

[ronjon]

hi folks,

I just recieved my AB aqualine fixture and was wondering... when i position the fixture the recommended 10" from the surface of the water, is it 10" from the bulb itself to the water or the bottom of the fixture to the water? a nit pick i know, but just wanted to be 100% before i start setting things up. hope to have some pics of the thing up and running in the next week or two.

TIA,
rj

[Ninong]

The official recommendation from AB-Aqualine is 30cm (11.8") from the bottom of the fixture to the surface of the water. I think you will be fine at 8"-10" from the bottom of the fixture to the water's surface.

They recommend 30cm in their set-up instructions but I have seen dozens of pics of German tanks with AB fixtures that are mounted about 8" above the surface. I sent them an e-mail and received a response from their technical dept. telling me that the recommendation of 30cm was for two reasons: (1) To allow for proper spread of the light, and (2) To prevent heating the aquarium water.

Ninong

[ronjon]

thanks for the answer to my question NINONG.

regards,
rj

[MtnDewMan]

Just thought i would provide a point of reference here. I have a 29 gallon reef with an HQI pendent installed under my canopy. The bottom of the pendent is about 5 inches from the water surface. With this amount of light over a 29 gallon, needless to say, the tank is saturated with light. I have had corals bleaching due to the amount of light. Only the most light demanding corals can stay thriving in the first 4 inches at the center of the tank. Then the intensity drops off as you go toward the sides and lower in the tank. 14 inches is the lowest leve in the tank (the top of my sand bed). I even have some light demanding corals near the bottom that do well. So with this all said, I can't keep many lower light demanding corals anywhere in the tank. I have to find them less lighted areas and sometimes shaded areas.

Don't get me wrong, I love the light and I love the corals that require that kind of light demand, just wanted to give you my experience.

[ronjon]

thanks for the info DewMan. the last set of MH lights that i had were 175 watters so this is a step up for me. my tank is fairly deep so i expect the "fall off' that you are talking about. i hope this will give me a bit of latitude in terms of what i can keep in my tank. i like the softies as much as that hard corals so this should work out just fine.

cheers,
rs

[SCETT316]

I have mine setup at around 9" above the wtr. level. I love the lighting I get, I am also supplementing with actinics, for the dawn/dusk effect and it looks great.
Thx to Ninong for recommending the fixtures. I am truly very happy with them.
Susan