richard@gryphon.COM (Richard Sexton) (11/17/89)
Yesterday I stated that the best tubes for growing plants were the
wide spectrum gro lux tubes. I've received some more information
from Sylvania, and I'm going to temper my comments a bit.
Sylvania reccomends mixing Gro Lux and Wide Spectrum Grow Lux
in a 1:1 ratio. Plants need the wide far red spectrum emitted
by the WS tube, but also the sharp peak of red emitted by the
gro-lux.
Interestingly enough, they have some sample setups for
terrestrial plants in which they use 1:1:1 cool white,
gor lux and gro lux wide spectrum. I'm not sure if thats
to supplant the blue end of the spectrum or just to provide
a better CRI, but either way, a 5500K tube such as a GE Chroma
50 (or 75), or Philips Colortone 50 or Sylvania Spec 50 would
probably be a better choice.
I havn't received any data from Philips yes on their version
of gro lux (``agro lites'').
Both GE and Sylvania make plant growth tubes. Sylvania owns
the trademark on ``Gro Lux''. GE calls theirs ``Gro and Sho''.
Both have wide spectrum versions of their plant growth lights.
The spectra appear to be roughly equal. The graphs they sent
me use different scales, but they appear to be the same curve
when allowences are made. If they are different, it's not
by much.
The one BIG difference is the variery of sizes and shapes these
tubes come in.
GE is the loser here. They make their tubes in 18 inch, 2 foot
and 4 foot, and thats all.
Sylvania makes:
Gro Lux:
8 watts 12 inch
14 watts 15 inch
15 watts 18 inch
20 watts 24 inch
30 watts 36 inch
40 watts 48 inch
115 watts 48 inch Very High Output (VHO)
160 watts 72 inch VHO
105 watts 96 inch High Output (HO)
215 watts 98 inch VHO
In Gro Lux Wide Spectrum:
15 watts 18 inch
20 watts 24 inch
22 watts 9 inch diameter circular
25 watts 42 inch
40 watts 48 inch
115 watts 48 inch VHO
160 watts 72 inch VHO
105 watts 96 inch HO
215 watts 96 inch VHO
215 watts 96 inch VHO with reflector
This last one (with reflector) is kind of interesting. There
is a piece id metal inside the tube that only allows light to
be emitted through a 235 degree opening. Do not install them upside
down. Ahem.
Also interesting is the 9" circular tube. Usefull for hex xhaped
tanks, although it would be more usefull if it came in other
(larger!) sizes.
Note that the wierd sized 42" tube is a T-6 tube, which is to say
it's thinner than the 1 1/2" T-12's.
Particularly annoying is the lack of a 36" wide spectrum tube. They
make it it gro lux, but gro lux wide spectrum.
The longevity figures for these tubes are rather intersting.
From 12 inch to 36 inch, 7500 hours.
24 inch is 9000 hours.
48 inch is 20,000 hours.
96 inch HO is 12,000 hours.
48, 72 and 96 inch VHO's are 10,000 hours.
9 inch circular tube is 12,000 hours.
So it seems 48 inch is really the size to use, a fact you may
want to take into consideration when building any permanent housing
for a bunch of tanks. Take this from somebody who has a bunch
of 36 inch tanks, and a 72 inch wide stand housing most of
my tanks.
--
``He is good with numbers, but I keep having to tell him how to
work the VCR over and over again'' -- Rajan Mahadevan's roommate
richard@gryphon.COM {routing site}!gryphon!richard