Light Bulbs

[hilltop452]

I have a 38-gallon tank with a MH. My question is about the bulbs. How can a figure out how many "k" a bulb is if I only know that it is a 90w, 120v, with a light out put of 1280 lumens. I think there is some formula for figuring this out. If anyone can help me with this I would appreciate it.
One other question...
I currently have a mercury vapor bulb in the MH. I noticed how yellow the light was and put a blue gel over part of the fixture to offset this. What are your thoughts about using this kind of light setup on my tank and what might be some cheap (if that's even possibel) alternatives?
[ May 14, 2001: Message edited by: hilltop452 ]

 

[mr . salty]

A 90 watt MH bulb.I can't say that I have ever heard of,or seen one that small on the market. Where did you get this setup?? And are you sure that it is only 90 watts?? If so,you may have a real problem finding a good 6500k or better bulb for it.Like I said,I have never seen anything smaller than 150watts.And even those(150's)have a very limited selection for bulbs.As far as the blue gel goes,although it may change the color of the light,I believe it does nothing to change the k-value of the bulb,or the light entering the tank.Plus the heat from this bulb could possibly melt the gel.

 

[hilltop452]

The bulb is a 90w. The fixture is 175w. I'm trying to get a feel for what the amount of lumens is generally in K or how I can figure that out.