[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Light bulb advice

Wright Huntley wrote:

I have been switching to compacts for my small tanks and buying electronic
ballasts in preparation for converting my larger tanks to the far more
efficient T-8 tubes. You get substantially more light from a 32W 4' T-8
(with a proper reflector design) than any 40W NO 4' T-12. [This is
particularly true in long narrow tanks, like 55G, where re-strike eats gobs
of light.] With instant-start electronic ballasts the total electrical
efficiency is great!

I reply:

Do you have an idea of how close is too close for fluorescent lamps? I have
tried to find this out for quite some time but I haven't managed to find a
clear answer.

Wright wrote:

There are some fine T-8 choices of phosphors in the 4000-6000K color range.
Get higher if you want bluer, and lower if you want yellower/redder (and
better growth, probably). If I could afford it, I would retrofit all three
of my 55G tanks to power compacts, but the T-8s should come close, if I can
build or buy suitably designed reflectors (the one big key to really good
use of light).

In mine, I'm going to stick with my used 55Gs (they are really cheap at the
thrift shops!) and probably install three or four T-8 5000K 32W tubes over
each. I'll either make new "Golden Arches" effective reflectors with 3M
"Silverlux" lining, or just buy the enhanced aluminum reflectors from Kim at
AH Supply for them. [http://ahsupply.com/index.html -- I have no connection,
just a happy customer]

I reply:

This is one of the problem with T8s. It is hard to buy or make reflectors
that can compete with AH Supply reflectors. You need more reflectors because
the T8s even with the right ballast are still less intense than the PC
lamps. I have the equipment to make reflectors and they work very well but I
don't get enough light in a deep tank if I make single lamp reflectors more
than 4" wide. I have tried to make two lamp versions but two T8 lamps in a
single reflector just doesn't seem to work. The ultimate in aquarium
fixtures would be linear T5 HO lamps with one specular reflector per lamp
made from a highly reflective material. That is one of the reasons I am so
interested in the merits of 800 series lamps. They don't make the T5 HO
lamps in 900 colors. In any case though, such a fixture would not be all
that much better than an AH Supply kit and not nearly as versatile as PCs.
Do you know offhand what the reflectivity of the 3M material?

The other problem with T8s when compared to PCs is that they are designed to
work at 25 degrees C. while T5 lamps are designed to work at 35 degrees C.
Most aquarium hoods are going to be closer to 35 rather than 25 degrees C.
On the other hand T8s are somewhat more efficient than PCs to begin with and
last longer as well so the T8s should be cheaper to operate.

Wayne Jones

My DIY planted aquarium homepage: