Re: Does LUX Matter?

On 1 Dec 2003 18:12:33 -0800, [EMAIL PROTECTED] (Nick D) wrote:

>Hi all...
>In my futile attempts to grow plants in my fish tank, I just purchased
>a Hagen Sun Glo which has 125 Lux reading for a 24" bulb, which I
>assume could grow some plants. On my next trip back to the Fish Store
>I notice a Hagen Life Glo which had 235 Lux reading. Apparently, as I
>understand it, Lux is a reading of Light Intensity (in a nutshell). So
>I'm wondering if a light with a higher Lux reading is better at
>growing plants, than say one with a lower reading. I am currently
>searching for the most powerful florescent tube I can find to grow
>plants in my 29gal. I realize spectrum has a lot to do with how well
>plants grow, but with only 2 tubes over my 29gal I need all the
>intensity I can get, right?
>
>Thoughts, Suggestions?
>
>Thanks,
>Nick D.

Hi Nick,

Intensity is important, but just as important is color temperature.
Various claims are made by manufacturers concerning their bulbs, as
they tend to be high dollar items - most of which is unjustified.

The unit of intensity measurement known as lumens is more frequently
used in measuring lamp intensity.  LUX is a unit of illumination equal
to 1 lumen per square meter; 0.0929 foot candle.  CRI is a measurement
of how much like "sunlight" a lamp appears to the human eye.

Problem is, many intensity measurements are made with the human vision
spectrum in mind.  Thus what YOU see as a bright light, may not appear
as bright to plants in the photosynthetic realm.

With that said, 2x 20 watt bulbs are NEVER going to be bright enough
to grow many plant specimens - period.  You can throw money at bulbs
manufacturer/vendors all day, with all kinds of specifications, and it
just won't help.  You can slowly grow low light plants, anubias,
crypts, and a few others, but that is it.  You need more light at the
correct color temperature to grow medium to high light plants.

One of the best PAR bulbs is a common 5000K tri-phosphor fluorescent -
available for about $3.50 at most commercial lighting vendors - maybe
even at your local Lowes or Home Despot.  Phillips, Sylvania, GE all
make these bulbs.  Chroma 50, Colortone 50, Designer 5000k, Ultralume
5000k, Alto Advantage 5000k, etc.  Switching to T-8 bulbs (and
matching electronic ballasts) opens up a new realm of bulbs that are
more efficient and have more choices available.

Read more than you wanted to know here:

http://www.thekrib.com/Lights/faq.html'

Greg