Well, consider that a 175W bulb still consumes 175 watts regardless of the
type of bulb. The ballast adds a bit more. Of course, this is all
predicated on the assumption that your 175W light puts out the same quantity
and quality of light that mine does. A 175W incandescent bulb is very
different from a 175W MH bulb (or a fluorescent).

My ballast plus lamp are rated at 1.8 amps. At 110V nominal, that works
out to be about 200 watts. I run my lamp 12 hours a day, so that's 2.4
kilowatt-hours. I haven't looked at my electric bill lately, but if you
figure $.15/kwh (a highish estimate, but realistic), that's $0.36 per day,
or $10.80 per month. Now unless you are dirt poor or are a starving grad
student, I don't think $11/month is a big deal.

As for heat, MH bulbs *seem* hotter because they are concentrated point
sources. The equivalent wattage fluorescent bulbs put out more heat, but
because they have so much surface area, they seem cooler when you put your
hand near them (you're only sampling a small bit of the radiated heat output
because your hand is small compared to the gross bulb area). And some
fluorescent ballasts aren't that efficient either. They can put out lots of
heat too.

Jeff


"Christopher" wrote in message
rthlink.net...
Actually I was more interested in the power bill costs than the initial
setup costs, I really have no way to change the lighting of my tank, and
in
all honesty no desire to do so.