Re: Lighting, from another angle

> From: "David W. Webb" <dwebb at ti_com>
> Date: Thu, 31 Oct 1996 14:16:58 -0600
> I recently purchased 4 30g breeder flats (24"x24"x12"h) that I intend
> to try deep parabolics on.  I'll keep people informed based on
> subjective readings (I don't have a light meter).  I'm expecting to
> focus up to 70% of the light from the T-8 tubes, potentially gaining a
> significant intensity improvement, speculated at 3x to 4x.
> If it doesn't work, I'm out the money for the metal I use for the
> reflectors and the time for setting them up.  :-)
> If it does work, I may be running single tube setups over my 12" wide
> tanks before long.


You didn't mention what you were going to breed in these tanks, but
for plants ...

Assuming a single 24" 20W bulb with 1500 lumens (very generous)
lighting a 24"x24" surface area gives 2,800 lux at the surface
assuming a 70% reflector.  (Lux = lumens per square meter)

2,800 lux isn't very bright for most plants. 

7,000 to 10,000 lux is better.  We have 15,000 lux over our 20" tall