NANFA-- Actinic lights

Irate Mormon (
Fri, 13 Feb 2004 19:28:55 -0500

Snipped from rec.aquaria.freshwater.plants - I'm sure there is lots more
relevant info as well, I just haven't had time to wade through it yet.

> 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 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.)

<end snippet>


Jackson, MS
/"Unless stated otherwise, comments made on this list do not necessarily
/ reflect the beliefs or goals of the North American Native Fishes
/ Association"
/ This is the discussion list of the North American Native Fishes Association
/ To subscribe, unsubscribe, or get help, send the word
/ subscribe, unsubscribe, or help in the body (not subject) of an email to
/ For a digest version, send the command to
/ instead.
/ For more information about NANFA, visit our web page,