I don't think it's so much that the algae does better at higher spectrums as
that the higher plants don't do as well as they might at a lower spectrum.

I've sometimes mixed 5300k bulbs with 10,000k bulbs but, frankly, over the
years, I've gotten used to and kind of like the more yellow light at lower
spectrums.

kush

LeighMo wrote in message
...
Only anecdotal, I'm afraid. I've been talking to many people over the
years
about lighting. An often quoted opinion is that "anything above 6000 K
will
encourage algae."

I've heard that "blue light causes algae" thing, too. That's the main
knock
against actinics.

But it hasn't been a problem for me. I've tried different color bulbs,
and
find I like 10,000K daylight best (so far). Just because I like the
"white"
look of the light. I haven't noticed any difference in algae. However, I
have
noticed that plants seem to grow taller with the 8800K than with the
10000K. I
suppose that makes sense. The 10,000K are meant to simulate light at the
water's surface, while the 8800K are meant to simulate light a few feet
below
the surface. The 8800K makes the plant "think" it's deeper.


Leigh

http://www.fortunecity.com/lavender/halloween/881/