"Nick D" wrote in message
om...
Hi...
I'm upgrading my lighting to power compacts and have the option of
getting several different kelvin rated bulbs. I realize that the
higher the kelvin rating, the cooler the visual of the bulb appears. I
don't like my tank looking yellow with a 5500k bulb...so I want to get
a 10000k bulb for a crisper white light, but I've heard that I cant
grow plants very well with 10000k? Is this right? Is 10000k considered
a salt water/ marine bulb?

Yes. If you put a 10000K bulb over a planted freshwater tank, chances are
that the only you will grow are algae.

I spoke to the Giesemann technical people about this at length, and they
do not recommend to go above 5700K. Yes, the light looks a bit yellow,
similar in color to what you get from an incandescent light bulb but it also
discourages algae. You might get away with 6700K, but I would
definitely not go above that. (6700K looks quite white, even a little cold,
at least to my eyes. I suspect that 10000K would look positively awful
on a planted freshwater tank.)

Cheers,

Michi.

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