Fluorescent Tubes

Subject: fluorescent tubes.
> I am replacing 2 cool-white bulbs with proper plant bulbs pretty
> need some advice as to what bulbs to get. The bulbs are all 48"
> I live in Australia and bulbs are really expensive.
> The only reasonably priced bulbs at the only mail order place in
> are the "Aqua-Glo" and "Aquastar". These are $16 each.
> Which of the above is better? i plan to buy 2 or 3 bulbs. Depend
> much the pump for the wet-dry costs. Should I get a mix of them
> Some info form the catalogue about each bulb is:
> Aqua-Glo
> - -Standard intensity
> - -Stimulates plant growth
> - -Intensifies natural fish colours

This is "advertising talk" and doesn't tell you much.  To decide 
what bulbs to purchase, you need to know:

Lumens/watt - should be as high as possible
Color temperature (degrees Kelvin) - Should be close to 5000K
Spectral graph - You want to see an "M" shaped curve, strong in 
the red and blue areas, with a spike around 5000K.
> Aquastar
> - -Long life triphosphor tube

Triphosphor is good. 

> - -Colour temperature 10,000 degrees K

This is too high.  Sounds like something meant for a reef tank, 
not for plants.

> - -Maintains brightness over time

That's good, but probably only true if used with an electronic 

> - -Promotes photosynthesis and chlorophyll synthesis

"Advertising talk" again.  Get a look at the spectral chart.

Red light promotes long lanky growth, while blue light promotes 
"bushy" growth.  Far red light stops growth (at least in 
terrestrial plants, and I'd bet aquatics aren't much different in 
that regard)

> p.s. just to show how expensive bulbs are here Power-Glo and Flo
> $28 each, Life-Glo is $53. Another shop also sells Coralife dayl
> $50 each.

Try traditional (particularly commercial) lighting sources rather 
than aquarium sources.  I suspect you'll find the prices much 

Karen Randall
Aquatic Gardeners Assoc.
Boston, MA