Metal Halide Question (s)

[phyre]

I recently aquired a free MH Ballast from a closing factory. After researching the ballast a bit I know its an M59 based ballast. From what I can tell that limits me to a 400W lamp. I have a 125 Gallon tank with a small cluster of star polyps and a few mushrooms. I do wish to branch out to some corals that require a higher light source and would like to use this ballast. Is a 400W bulb going to be too strong? My tank is standard 24" deep, 6 feet long. Im limited to 18" of height above the tank to place the lamp ( bulb to water surface)
Im also curious to know if this isnt too strong should I mount the light directly in the middle of the tank or off to one side keeping the lower light corals on one side? Thanks in advance to all who try to help!!

 

[Anonymous]

400W is a bit much form mushrooms and star polyps, but if you mount it properly, it can work, just not the best way to support your electric company. Light intensity fall pretty fast if you mount it off the side, so that may work for you. You can also limit the amount of time the light is on, say 6 or 8 hours instead of 12 hours.

 

[phyre]

I thought it was a bit high as well, like i mentioned in my first post, im looking to branch out in the coral area with some that require higher lighting, im not concerned with maintaining my polyps and mushrooms as they are doing fine with the lighting i have now, i can move them away from the halide if i mount it up to one side. I just dont want to overlight everything in the tank

 

[Anonymous]

Just cut down the light hours in the begining, and watch the tank temperature. A lot of low-light critters can adjust to high light over time. Used to have 2X400W+2X96W over a 60 gal with mushroom with no problem. Stopped doing that setup when I started to pay my electric bill.

 

[Len]

You can use lower output 400W bulbs (like 20,000K rated bulbs).

 

[phyre]

I was also considering using a screen diffuser for the first couple of weeks, layering some aluminum window screen 4 or 5 layers deep and removing a layer every couple of days to lessen the shock of it all

 

[phyre]

Thanks Len, I had actually already looked into an xm 20 000 k for that exact reason! Glad to know I was on the right track, Lighting wattage, colour etc has always seemed confusing to me!!