"Ian" wrote in message
y.com...
I am planning on using it over a 75 Gallon tank
(48X18X20). I'm wondering if I need to invest in 2 pendants. I would prefer
one 250 Watt MH pendant for simplicity and for costs. I figure I can hang
it over my tank and get several light zones, i.e. high light need plants
would be directly under the glow, slower growers in the periphery. Any
thoughts?

I don't think you can get away with a single pendant for a 48" tank.
You'd end up with much of the tank being awfully dark.
I would use two 150W pendants. That will give you just over a watt
per liter, which is a little on the high side but, with CO2 and nutrients,
you'll get spectacular plant growth.

Cheers,

Michi.

--
Michi Henning Ph: +61 4 1118-2700
ZeroC, Inc. http://www.zeroc.com