HPS

["Richard J. Sexton" <richard at aquaria_net>]

>A guy here at work just gave me a High Pressure Sodium light, 250watts. Is
>this any good for growing aquarium plants? I'm setting up a mangrove tank,
>would it be good for that? He's also giving me a metal halide bulb (I guess
>he was really into growing some sort of plant in his basement when he was
>younger. Go figure!) Any source known for an inexpensive metal halide
>housing/ ballast? I don't know too much about these sorts of lights. I've
>also been tinkering with halogen and xenon bulbs. Neither seem to work that
>well.

a 250W HPS lamp puts out a ton of light, mostly in the red. It will work
fine but red ligth tents to elngate the internodal distance in plants. It
may not be enoug hto bother you. The yellow cast might be, you could
offset this with a mercury lamp which is primarily blue.

There's no such thing as a cheap metal halide ballast. Mercury and HPS
can be had cheap as outdoor safelty lighting.

No, incandescets will not work well except as ancilliary lighting, say
to compliment not great (warm whiet, cool white) fluorescents. You will
see lots of old pictures of huge tanks with say 4 4' fluorescents
and maybe 5 or 6 40 W incandescents.

I've noticed that Echinodrus do better with incandescent supplument
or even full incasdescent in small tanks. Don't know why.



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