RE: [APD] Failed CF Retrofit - Don't let it happen to you!

["Bob Crosby" <rtcrosby at charter_net>]

Try www.ahsupply.com for your components. They are far less expensive
than what you related and they have schematics to retrofit compact
fluorescents. I had a similar "standard" hood for a 29 gallon and
ordered from them a retrofit kit including reflector, ballast,
lampholders, etc. (even nuts and bolts), a 55 watt 5400K bulb (they
offer 5400K, 6700K, and 10,000K), and detailed instructions (free) and I
spent just over $70 including shipping. I've had this rig running 8-10
hours a day for the last year with no problem whatsoever.

Do you have ventilation in the top of the hood? Otherwise I can't see
why you'd create enough heat to crack the glass. I can put my hand on
the underside of the glass of my hood and it is warm enough to be
uncomfortable if I touch it for 4 or 5 seconds, but clearly not enough
to crack the glass.

 
-----Original Message-----
From: aquatic-plants-bounces+rtcrosby=charter_net at actwin.com
[mailto:aquatic-plants-bounces+rtcrosby=charter_net at actwin.com] On
Behalf Of Robert Zink
Sent: Wednesday, March 24, 2004 1:35 PM
To: Aquatic-Plants at actwin_com
Subject: [APD] Failed CF Retrofit - Don't let it happen to you!


Greetings to all list members from a new subscriber!

Well, I should have consulted this list first, I think I wasted a lot of
time and money. I designed and retrofitted my own light hood and it
appears to be both inadequate and faulty.

We have several vintage Metaframe tanks, stainless steel corners, slate
bottoms. Also have a couple of matching Metaframe stainless steel light
fixtures, some as a full hood, some just the light (incandescent). We
really enjoy the "retro" look, especially when they are kept on their
contemporary wrought iron stands.

Obviously, these 40 year old light fixtures are pitifully inadequate, so
I got it in my head to design my own retrofit for one of the fixtures
that fit our 20 GH as an experiment. Well, spatially and aesthetically,
the experiment was fairly successful, but the performance is a failure.

I took my first creative cues from the existing incandescent design.
This was a double socket mounted in the center of the canopy, so that
the bulbs were held horizontally, opposite each other. I began to search
for compact fluorescent lamps of high luminous intensity that could
occupy roughly the same amount of space as the incandescent bulbs. I
settled on 42W GE Biax T/E (F42TBX/840/A/4P). Once my special order came
in at my LES, in exchange for approximately 100 greenbacks, I had the 2
aforementioned lamps, the 2 GX24Q-4 lampholders (Leviton H42A), the
electronic ballast (Advance ICF-2S42-M2-LD), a new nickel-plated canopy
switch, 8 feet of 14-3 appliance cord, and a rubber grommet (which I had
to buy 5 in the blister pack).

I took it all out to my shop, dug out some wire nuts and a wall socket
plug, and put it all together. I had originally intended to have the
ballast remote from the fixture, on the floor, but it was so compact and
cute that I mounted it piggyback outside of the reflector. I fabricated
mountings for the lampholders. The two small bolts that held the ballast
on also held these metal brackets in place and provided a fastening
point for ground. In the end, I only needed to drill 3 new holes in the
stainless steel shell and enlarge the existing zip cord hole.

As I peered into the now-shadow-free reaches of the aquarium, I was
extremely pleased with myself. With output rated at 3200 lumens apiece,
I thought, "Wow, 6400 lumens. You are awesome."

Well, about 2 hours later is when my bubble burst. I heard a loud TIC!
When I surveyed the situation, I found the 3/16 inch thick canopy glass
beneath the fixture had cracked. My wife said, "I told you it was too
hot!" Being a male, I said, "Don't worry, I told you, they are designed
to run that hot. I just made the mistake of keeping it too close to the
glass." I went out to the shop with some supplies we had on hand and
came back in with 4 feet made of cork that slipped on securely; not only
holding the light at a safer 1 inch distance away, but also provided
extra stability and slip resistance.

So far so good. The canopy glass was a bummer, but I figured, "You gotta
break some eggs if you want to make an omelet."

Two days later. Enjoying a bright tank with some new plantings that were
now possible. Push the switch in the morning and just a brief flash -
then nothing. Testing revealed that one of the 12,000 hour lamps had
already burned out. Now I was really crestfallen.

I decided to do the research I should have done before throwing my money
out. My wife was right -- boy, that right there really hurt! :-( The
fixture was too hot. Being open at the bottom only was not enough.

But I found out more than that, and that is why I turn to you folks for
help. These 4000K lamps are the brightest color these 42 watters come
in. Not even enough for good sustained plant growth in the first place.

So finally I get to my question. I want to go back to the drawing board.
What type of suitable lamps can I put in this hood as it is?

Inside, it measures 23 inches long, 3.5 inches wide at the bottom, 1.5
inches wide at the top and 2 inches high. Cross sectional shape like
this:

 __
/  \

I'm guessing that I will need to provide some openings in the top for
cooling by convection, no matter what type of lamp? One possibility was
to drill multiple holes close together on a grid spacing. Any thoughts
on that? I wish I could do something without compromising the original
outward appearance too much.

I will be stockpiling the parts from the current "experiment." Is there
any sense in making plans to incorporate these parts in a future
from-scratch hood design for a bigger tank, like a 55G? I mean, what
lamps could be paired with these to give an acceptable spectrum for the
future. The ballast can run 1 or 2 of these bulbs.

Thanks so much for any light you can shed!  ;-)
-- 
Cheers,
Bob

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