400W MH How high?

[t.priscu]

Hi guys,
Wasnt sure if i should place this in the lighting forum or here but here goes.
I'm setting up a frag tank with a 100gallon black rubbermade tub. I'm not really sure how high to hang my 400W MH light above the water? I did do a search but it seemed like the answers were all over the place or it didnt really apply to exactly what i wanted to know because im not sure if the color of the tub(black) will soak up light. The water is about 25 inches deep in the tub, but there is no reason i cant build a rack inside the water if needed.

Here is the light if it changes anything.

Galaxy 400W Electronic Metal Halide Ballast
LumenBright 3 SE Mogul Base Reflector by
CoralVue
XM 400W 10,000K Metal Halide Bulb, Screw
Socket

Whats your thoughts and thanks for the help.

 

[N-dog]

whats the width and length

 

[t.priscu]

4 ft by 3 ft

 

[jeff@zina.com]

What are you propagating? There is no magic height to give you.

Jeff

 

[t.priscu]

Mostly Monti Caps & Slimer, stag horn that kind of stuff.

Just looking for a ball park idea. Lets say i have the corals in 12 inches of water, how high should the light be?

 

[Stupes]

Probably somewhere around 20 inches off the top of the water, maybe even just a little more than that. Using those reflectors they say to mount the lights about 16 inches off the water using 250's.

 

[t.priscu]

Very much appreciated.
I'll start at 20 and see where it goes.

Thanks for every ones input.

 

[tamn3]

I have the same lighting setup on my tank. I keep my light 8 inches above the water surface. My tank is 30" deep and it took me about a period of 2 months to acclimate some of the corals placed higher in the tank to the lighting.

 

[t.priscu]

I have the same lighting setup on my tank. I keep my light 8 inches above the water surface. My tank is 30" deep and it took me about a period of 2 months to acclimate some of the corals placed higher in the tank to the lighting.

Great! Ty for the input.

 

[flyyyguy]

Ive got some of my 400's as close as 8" as well, and one of the tanks in question is only 16" deep.

as already said, this is absolutely not a overnight thing. Start high, and slowly work into it. Yo-yo's are great for all lighting if you arent already using them. Makes it super simple to move them up,down and/or out of your way