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Re: Replacing CF Lamps



Tom Wood wrote:

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I started with three 96 watt AH Supply kits on my 90 gallon. Way too
much
light when you consider that they may be up to 160% more efficient than
the
lamp setups that the 3 watts/gallon rule is based on.

Wayne wrote:

There is no way a 96 watt PC is normally that much more efficient decent
fluorescent lamp setups. Aside from the electronic ballast which any
system can have, the whole increase in efficiency is based on the fact
that PCs can be used with a high quality computer designed specular
reflector. This means that more light can get through the air/water
barrier as it can be directed down at a better angle. Even if the
reflector were perfect in reflectivity and shape it could not produce
such a large increase in efficiency.

Tom wrote:

But I think a more important concern
is the effect of aging on the spectrum of light being provided. It's my
understanding that fluorescent lamps shift in spectrum toward a more
purple
range which may be less useful to plants, and more useful to algae.

Wayne wrote:

I have never seen any useful information on the spectral shift of
fluorescent lamps. I think it is mainly one of those aquarium myths. I
am sure that there is some due to the redepositing of electrode material
and the absorbtion of mercury into the glass wall but I do not think it
would be significant in a normally functioning lamp. I understand it is
an issue with UV lamps. If you have MH lamps it's a different story.
They can spectral shift big time.

Wayne