Re: [APD] Coral Sun Lights

[Wright Huntley <whuntley at verizon_net>]

Sandy,

The actinic is probably pretty worthless, if it looks blue. It will not 
show the green of plants or red and orange and yellow coloring very 
well. Much of the spectrum is probably outside the action spectrum of 
chlorophyll, so is likely poor for plant growth, too.. Use for 
deeper-water corals.

10,000K varies wildly from one brand to another. If it looks white, it 
probably is useful, but if it looks blue or purplish it still may grow 
plants OK but make things look pretty sickly.

The degrees Kelvin scale is supposed to be locus along a very narrow 
line running from red through white to blue-white on the ICI chart. It 
describes the way a heated blackbody "looks" to the "standard observer." 
A heated blackbody never looks greenish or magenta. Tubes do. For 
example "cool white" is way off the line to the green side. It is not 
"white" so I don't give a darn what Kelvin number they give it. It 
matches perfectly the dip in the action spectrum of normal  plant 
growth, so it takes more than twice as many Watts of "cool white" to get 
the same growth as a "daylight" or other tube (that may look a lot less 
bright).[There are exceptions: I think Riccia loves "cool whites."]

Unfortunately, this use of "Kelvin" is a psycho-physical scale, bearing 
no particular relation to the actual spectrum. To make matters worse, 
many aquarium bulbs are given a degrees Kelvin number, but actually are 
far, far off the line that describes blackbody appearance. Getting their 
actual spectrum is worse than pulling teeth. If you get it, it is always 
without any scale on the intensity axis (i.e., worthless).

I would use the compact fluorescent kits from AH Supply, and use THEIR 
"K" numbers in the 5000 to 6700 range for the best plant and visual 
results (respectively). This is highly subjective so others may fairly 
disagree.

I am currently retrofitting a 65G hood that came with 2 30W T-5s with 2 
55W CFs at 6700K and good Miro reflectors. This much increase will call 
for ferts and CO2 as a minimum. It should also make fish and plants look 
"real."

HTH,

Wright

> Date: Fri, 19 Dec 2008 14:12:27 EST
> From: Sandy1238 at aol_com
> Subject: [APD] Coral Sun Lights
> To: aquatic-plants at actwin_com
>
> Hi All,
>  
> I just won two lights a actinic 420 15 in.and another 18 in. showing  10,000K 
> on the box. Is either of these good for fresh water planted tanks? Will  they 
> show fish colors well? If I can trade them out what lights would be best  for 
> tanks up to twenty gallons?
>  
> Sincerely,
>  
> Sandy
Wright Huntley - 805 Valley West Cir., Bishop CA 93514
whuntley at verizon_net 760 872-3995. Cell 760 937-2276
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