On Sun, 14 Mar 2010 21:11:54 -0700, Father Haskell wrote:

On Mar 13, 2:08Â*pm, Larry Blanchard wrote:
OK, maybe waaay OT, but I've found a lot of general knowledge in this
group.

I have an aquarium hood that takes a 55 watt CF. Â*One of the U-shaped
ones with 4 in-line pins. Â*The fixture comes with dire warnings to only
replace with the same kind of bulb.

55 watts is too much wattage for the tank without some extra doodads
(mainly CO2 injection) - I get lots of algae growth. Â*Eventually the
plants will win out over the algae, but in the meantime ...

I went out looking for a new bulb. Â*Turns out they don't make 55 watt
any more, they make a 45 watt and a 65 watt. Â*The stores all tell me
the 65 will work, but they give conflicting answers on the 45 watt.

If someone here is well versed in the do's and don'ts of CF bulbs and
fixtures, please let me know if a 45 watt will work. Â*They're too
expensive to experiment :-).

Thanks.

--
Intelligence is an experiment that failed - G. B. Shaw

Pin base CFLs have the ballast in the fixture. You need the same
wattage.

So you're saying that a lower wattage bulb won't work? BTW, it seems 45
watt bulbs aren't available any more. I'd have to drop down to a 40 watt.


As for the bulb stimulating algae growth, that's due mostly to blue
output. 6500K daylights put out more blue and UV than 5700K "sunshine"
and 3500K cool whites. 6500K bulbs are great for plant lights and
hence for algae.

Agreed, but I have a heavily planted tank so want the 6500K. But your
post does suggest an alternate solution. I could switch to a less
effective bulb for at least a short time without harming the plants.
Once the plants grew to a respectable size I could go back to the plant
light. Thanks.

--
Intelligence is an experiment that failed - G. B. Shaw