Lighting

[SGTDirk]

I resently, lets say aquired Metal Halide Fixtures. 5 of them. This is the thing, they were not designed for aquariums. I can easily get them to hang but I have a couple questions. the Ballests are for 100W bulbs. I have found bulbs, but they are only 5.5K bulbs which isn't the 10K I wanted. Is it possible to double or triple the lights up to equal 11K or what not. I can get the bulbs rated at 175W, but as I stated the ballest is only rated to 100, You think it would work?? Lol.

[Richard]

The K rating is for the color of the bulb. So for 5.5k if you did 3 of them the formula would be...
Yellow + Yellow + Yellow = Very Yellow ;)

You could use them though if you don't mind the yellow color.

[GaryP]

5,5K is the color of sunlight. In theory that sounds like a good idea, right? But as Richard said, everything will look very yellow and brown. I ran 6.5K bulbs for a while. I got GREAT growth for them, but I didn't know there was such a thing as blue or purple corals under them. The lower K value bulbs are great in a propagation tank where your main concern is rapid growth, but not very good for color. 10K in my opinion is a good balance between growth and color.

Just another note in case you weren't aware of it. Generally, the lower the K value, the higher the PAR (photosyntetically available radiation). That is why you get better growth from low K bulbs like 5.5 and 6.5K bulbs. You can still use them, but you have to supplement with a lot of actinic (purple) light.

[alton]

Depending on the age of the ballast they could be only 50% efficient. The older MH ballast get the more power they draw and the less wattage they produce and the louder they get.

[JimD]

Unless its electronic.

[Bug_Power]

I use the standard HD 5.5k bulbs. I have a new tank and want growth. So after it starts to grow out I'll swap out my 250's for 10ks for 14ks

[Thunderkat]

I resently, lets say aquired Metal Halide Fixtures.

Ah ha! So you were the guy that broke into the jewelry store and stole the lights and left millions in diamonds undisturbed! :lol