Re: T8 vs. T-12

>From: krandall at world_std.com (Karen A Randall)
>Date: Fri, 10 Nov 1995 23:18:15 -0500
>Subject: T-8's, Trading Post and Cold Weather
>Subject: T8 vs. T-12

Edited ...

>Phillips and GE both produce 
>comparable bulbs, but the ones I use are GE SPX50 bulbs. I pay $5 
>each for them.  
>They are brighter than the comparable T-12 bulb, there is less 
>drop-off (20% over the entire life of the bulb), they run on less 
>electricity (a 48" bulb is 32W, and the ballast runs at -5%, so 
>the whole unit is _much_ less expensive to run. The SPX50 has a 
>spectral curve >>>similar<<< to a Vita Lite, and is a 5000K bulb.

I'm a fan of T8 bulbs also.  After talking with several bulb
and ballast manufactures, it seems that the commercial lighting industry
is rapidly shifting towards these more energy efficient bulbs.
What seems to be driving the industry are the new Federal Minimum 
Energy Standards for fluorescent lights.  The old F40T12CW cool whites
may be a thing of the past.

According to Grainger 1995 Lamp Catalog No. 105L, the GE F32SPX50
have a color rendering index of 80 while the Chroma 50 & Chroma 75 = Vita Lite
have color rendering index of 90 & 92 respectively.
My question is how high of a CRI is needed to grow just about all types of
aquatic aquarium plants?  
Most people agree that Vita Lites produce a good spectrum of light so a 
CRI in the 90s seem good enough. (I suppose it's possible to have a bulb fluorescent
bulb with a CRI of 90 and still miss the important blue/red photosynthesis peaks.  
But that would be difficult to do?)

Is a CRI of 80 good enough?

I've found that Micro Swords (Lilaeopsis novae-zelandiae??) - grass like plants
seemed to be sensative not only to enough light, but seem to grow best with 
a wide-spectrum type of lighting.  Does any think that using this plant to
compare the grow rate in Vita Lite compared to say a Philips Ultralume (CRI=85)
worth doing?

Ron Wozniak  Allentown PA, USA
rjw at aluxpo_att.com