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10000k and 6500k bulbs

Date: Sun, 24 Jan 1999 10:39:03 EST
From: TomWood3 at aol_com
Subject: Lux/PAR/Kelvin - Dana Riddle Light Analysis

I read Dana Riddle's book The Captive Reef and there is a chart in there
implies that the higher kelvin bulbs produce more PAR. See page 249
where the
chart shows that the PAR of a metal halide bulb is Lux divided by 75,
but the
PAR of a 10,000K metal halide is Lux divided by 30.  This implies that
10,000K bulb has more than twice the PAR of a regular metal halide,
given they
start with the same lux.  Based on that, I tried a 10,000K bulb and the
results were disappointing.  When I switched to a 6,500K bulb,
presumably with
lower PAR, the plants did much better.  What gives?


This is likely because the corals get the "filtered" light which at the
depths they have their niche .This light is bluish and the deep water
corals do much better with this "deep" light. You can't recreate a 50 ft
deep tank but these lights attempt to mimic the natural filtering of the
sea water.The 20000k bulbs are for even deeper corals and their
   Freshwater plants tend not to have any filtering effect caused by the
water generally so the 6500k does a great job .Most of our plants are
amphibious  and seasonally submersed.Most of these are extremely close
to the water's surface so sunlight isn't filtered very much by the
water.   It would be find to "mix" the 10000k bulb in with other lower
temp bulbs .Aleast you'll get some use out of it unless you want to
start that mini-reef(or have one already).You'll have a nice blue ended
spike that will be intense. Keep playing around with though. PAR for
reef ain't what it is for FW plants but maybe if we bug the manufactures
of plant lighting ..... we could get some "perfect" lamps(ALL types)
designed for us planties, based on PAR per watt and still have a nice
look to the eye. Oh, and it has to be cheap !
    I understand that cat feces ,when burned, also can be used as a
spectacular lighting source ,although somewhat acrid in odor.Replacement
lamps are cheap .Only cost one can of cat food.
The color temp is a black to light brown type of light but is extremely
intense and exudes a high degree of PAR( particulary aggravated reflux)
to the owners of such lighting systems.Getting the lights to "turn on"
can be tricky<g>.
Tom Barr    AGA