shielding/dimming MH

[astroboy]

I'm setting up a 90 gallon and I have an old MH fixture that I'll be using for the next year, two 250 watt 14K bulbs, 2 T5 actinics.

 

At this point I have only LPS corals which have been under 130 watts in a 29 gallon tank. I'm told the MH will probably be too bright. Since I'm renting the place I'm in knocking some holes in the walls or ceiling to raise the MHs isn't an option.

 

Is there some reasonably easy way to run MH bulbs so that they're dimmer? I've read one can switch out ballasts, but that's more complicated than I want to get.

 

Or, what would be a good way to shield the bulbs? I was thinking a couple thicknesses of glass might do the trick but I'm not sure how that would affect the color. 

 

Thanks,

 

Mark

[Origami]

One or two layers of window screen over the tank can cut a lot of light.

[freshfins]

you can make a light stand with 1/2" conduit pipe or copper pipe.  Example:  http://www.plantedtank.net/forums/showthread.php?t=130543

[steveoutlaw]

+1 to window screen.  If you don't want to do that, just get a couple of 2x4s to put under the fixture legs.  After a week, remove one and get rid of the second one after another week.  You'll be fine.

[sachabballi reef]

One or two layers of window screen over the tank can cut a lot of light.

Each week remove one of the screens and then your corals should be acclimated to the stronger lights

 

Sent from my DROID RAZR using Tapatalk 2

 

 

[Coral Hind]

If you ran 20k MH bulbs they are not as strong and would not burn the corals as easily. Run those for only 5 hours a day. Change the t5 so they are a 50/50 bulb and run them for a few hours before and after the MH to get the longer viewing photo period with less intensity. You would probably not need the screen except maybe for the first couple of weeks until the corals adjust.

 

Make sure not to add carbon or do a water change during the light acclimation period as the more clear water will allow better light penetration and burn the corals.