On Mar 13, 2:08*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. *One of the U-shaped
ones with 4 in-line pins. *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. *Eventually the
plants will win out over the algae, but in the meantime ...

I went out looking for a new bulb. *Turns out they don't make 55 watt any
more, they make a 45 watt and a 65 watt. *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. *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. Pin base CFL bulbs are also cheap, because
you're only replacing half of the functioning unit. Buy the same
wattage generic bulb from Walmart, HD, whatever, instead of
the repackaged, marked-up specialty bulb from the fish store.
The only difference between bulbs of a given output is color
temperature (degrees K). Match that figure, and you have
the exact replacement.

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.