changing to MH lighting- questions on options

Hi

I am seriously considering making a change on my reef tank lighting
from 6 x 80 watt T5s
and want to use 250 watt MH lamps with T5 supplemental

I have been looking at various canopy options available to me here

my problem
I have a 5ft tank with plastic centre brace, thus dont want a MH in centre

twin lamp canopies are only 48 inches long
three lamp canopies are 60 inches long

my idea is to purchase a 3 x 250 watt lamp canopy
and then remove middle lamp so it does not melt the plastic

question

will the placement of the remaining 2 illuminated lamps be OK? or would they be so far apart that I would get a shadow in the centre of reef

looking to get 2 x 14k mh Lamps and 4 x T5 unit ( T5s will be 2 x Actinic 22k and 2 x 14k ) Thus I can gently phase in the MH whilst still running 2/3rds of the lighting I currently have

Steve

 

from what i have heard depending on how high you keep it, each one reaches roughly 2' by 2' area..now im not sure about which reflector and stuff so you may be able to get the best brand reflectors and rise them higher and be just fine..

i have 1 250 over my 30 gallon and it is 30" long i think supplemented with actinics..

you could also try 2 400w and rise them to where it could cover the whole tank with grade A reflectors..

i just dont know how high you would have to keep them to cover, and when you did that with the 250, you might not have enough light, so the 400s might be better off..

just trying to throw some ideas out..

 

Hey Steve, why do you want to add MHs, just for more output? T-5s are pretty good...

That said, I am using a mix of t-5s and a 250W MH on my 30x30x24 cube.

The key really is the reflector. I am using a lumen bright mini-wide, with the bulb about 16" above the water. The surface of the water is maybe warm, but not at all hot. Coverage for 30x30 is more than adequate. I don't have a par meter, but from the reviews I've seen, a 250 with a good reflector can perform more like a 400 with a basic reflector.

I don't know if you'll find a tall canopy though. For my setup I decided to build a fixture and hang it from the ceiling. Here is a pic I took when I first set it up. You can see the brightness and coverage. For reference, the tank to the right is a 29g with 4x24W T-5 lighting. I think two would cover the tank fine, but at that height you *could* have three without heat issues....