Lighting -- Try as I might, I just can't figure this out..

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Phyl

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I have Current USA 4x65 (2x10K, 2xActinic) in a 48" fixture over my 120g tank. 2'ish watts per gallon. My LFS that sold this to me told me that I'd be able to keep a good variety of corals with this. Seems to me that 2'ish wpg isn't really very much light at all. What could I actually keep with this amount of light?

What do I need to do to get this tank up to the 3-5wpg range? Do I add another light? Do I need to replace this light with a MH? Everything I've read about the MH suggests that it needs to be high up off of the tank. My tank hood is only 5" deep or so. Does that mean that MH are out of the question?
 
You can actually take apart that fixture and use the pieces in a DIY MH hood if you want. Inside the fixutre is just a couple ballasts, some wiring, end caps, and switches which can all be used outside of the fixture.
 
I'm not sure you'd want to put MH in a hood with only 5" of clearance. Heat might become an issue. I'm not an expert on MH lighting though and I'm sure there are members who can tell you exactly how close to the water the fixtures can be. You could, as recommended above, DIY a PC fixture using the parts from your existing fixture. Check with www.ahsupply.com for PC retro kits. I'd say if you doubled your lighting, you would certainly be able to keep soft corals and polyps. If this is a 4' tank, and I'm guessing it is, SPS, clams, and anemones are going to require MH due to the depth of the tank. One option might be to open up the top of the hood and hang some MH pendants? Not sure how your hood is designed or whether you'd want to cut it.
 
Most of your leather corals would do alright in that light. I have a 125 with 330w and my leathers do well. I have some hard corals in there also.
 
If you do a DIY MH and given the depth, I would do either 250w or 400w. Each MH covers 2 feet. Just make sure you are about 12-15 inches above the water. These babies get very hot! I had to build a canopy for mine because the 6 inch clearance was not enough.

Mike
 
I have a 150 watt de pendant and it gives off about half the heat a mogul bulb puts out. I have mine 8" off the water on a 36" tank and there are no dark spots.
 
edmonton, what is the depth of your tank? do you supplement with actinic lights? i am thinking of getting a 150 DE for my 29 and then adding a second one when i upgrade to a 65g. what K is your DE?

wow, that was a ton questions. sorry

steve r
 
I had a similar light on my 75 and it did great but the 4ft 120 gal tank is very deep. Low light corals might be ok on the bottom but you would have to put some higher light stuff closer to the top. I am sure you should be fine unless you want to add some hight light corals.

MH's are awesome and you would only need 2 but they do generate quite a bit of heat. I have a 2x250 on my 75 and I love it. My lights are about 10" off the water. MH retro kits are pretty cheap but you might have to modify your canopy to allow more clearance.

If you don't want high light corals then keep what you have.
 
You really want the MH bulbs at least 6-8" off the water surface. This is for safety as well as heat. Any water that hits the bulb could cause it to explode. You could also do a VHO retro kit in your hood. 4 110 watt tubes would be fine over your tank and allow you to keep most corals with the exception of SPS and clams. Or you could remove your hood and run a Hamilton Metal halide hood that has the MH bul;bs and actinics contained in one unit that sits right on the tank.
 
The tank I have is an oceanic with a beautiful cherry finish stand and canopy. It is in the middle of our entry way and is really quite a showpiece. Can I put that hamilton hood inside my oceanic canopy? That would be *ideal*.

Thanks!
 
You could you would just have to clear the inside out a bit for the fans. They stick out 1/4 on each side and need a way to get air.
 
Thanks Darin, I think that's my answer. Will the tank likely need a chiller on top of the fans or will they be enough to prevent overheating?

Thanks!
 
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