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T-8 fluorescent Bulbs


  1. T-8 fluorescents
    by krombhol-at-felix.TECLink.Net (Paul Krombholz) (Sat, 11 Nov 1995)
  2. T-8's vs T-12's
    by (Mon, 13 Nov 1995)
  3. Which T8 bulbs to buy?
    by (G.Tong) (Sat, 30 Dec 1995)
  4. Which T8 bulbs to buy?
    by (Jay Bickford) (Sat, 30 Dec 1995)
  5. T12 Electronic ballasts
    by (Neil Frank) (Fri, 17 Nov 95)
  6. Tank Lighting?? Help
    by Thomas Murphy <> (Wed, 23 Oct 1996)
  7. Blue Light
    by (Fri, 14 Feb 1997)
  8. Plant Lighting
    by Davis & Lanelle Chastain <chastain/> (Mon, 24 Nov 1997)
  9. Lighting
    by "G Tollefson" <g.tollefson/> (Thu, 19 Nov 1998)
  10. Phillips T-8 80 series
    by "Adam R. Novitt" <novitt/> (Tue, 22 Dec 1998)
  11. T-8 lighting
    by "wayne jones" <waj/> (Fri, 23 Jul 1999)
  12. T8 electronic ballast wiring
    by Dan Dixon <dandixon/> (Mon, 07 Feb 2000)
  13. 36 inch lighting
    by zxcvbob <bob/> (Thu, 20 Jul 2000)
  14. More T8 Stuff
    by busko/ (Ivo Busko) (Mon, 7 Aug 2000)

T-8 fluorescents

by krombhol-at-felix.TECLink.Net (Paul Krombholz)
Date: Sat, 11 Nov 1995

>From: Veselis_Robert_A/
>Date: Fri, 10 Nov 95 11:39:08 -0500
>Subject: T8 vs. T-12
>Item Subject: Text_1
>     >Hooray!!! Someone else who's dicovered T-8's.  Remember that the
>     watts-per-gallon rules are _very_ rough.  T-12's vary considerably
>     from one bulb to another.  When I do estimates on what I'll need using
>     T-8's, I figure as if they were 40W bulbs. (I know they're brighter)
>     It's amazing to me how many people are still paying the costs (up
>     front, replacement and electrical) for T-12's!<
>     Excuse my naivete, but what is a T-8 and what is a T-12? Do you need
>     special fixtures for T-8? Sounds like I should only get T-8 bulbs. How
>     do I know this when I'm buying them in the store?
>     Bob.

T-12's are the common, 1.5 inch diameter fluorescent lights.  T-8's are
only 1 inch diameter.  They are brighter, and you can pack them closer
together.  I made a light fixture for a fifteen gallon plant tank that has
four two foot T-8's, run by an Advance electronic ballast (REL-43P2-RH-TP).
This ballast can run 3 or 4 T-8's, which can be 48 inch, 36 inch, or 24
inch bulbs.  It cost me around $26.00.  Using a light meter, I found that
the four T-8 bulbs put out about twice as much light as three T-12 bulbs. I
agree with Karen.  T-8's are definitely better than T-12's.   I have plans
to replace the two T-12's on my 55 gal with four T-8's and the four T-12's
on my 75 gal with eight T-8's.

T-8's vs T-12's

Date: Mon, 13 Nov 1995

In a message dated 95-11-13 15:53:01 EST, Hardjono writes:

>Subject: Re: T-8 fluorescents
>So how do you convert T-12 fixture to fit T-8 tube ?
>       1. Ballast:
>               What is a good brand ? Where to get them ? Any mail order ?
Brand - We've* had the best luck with Magnetek and then Motorola. Advance
ballasts have given us fits - both with the failures and the negotiated

Where - Grainger handles them if you have access.
>       2. End caps:
>               Do I need to replace the end caps since T-8 has 1 inch diameter
>               and T-12 has 1.5 inch diameter ?

Although expensive as anything - Pet Warehouse has some inserts but I'm not
sure if they would separate them from the total set. These endcaps look like
an excellent DIY opportunity - $16-19/pr!

>       3. Starter:
>               Do I need a starter with the electronic ballast ?
Nope - refer to the excellent explanation offered previously about rapid
start, instant start, etc.
>Is there any T-8 tube for 18" fixture ?
Yes - see one of the large mail order places if local shop does not have.

* - the 'we' I refer to above is a collection of facility managers,
engineers, etc. that try to save energy in a very large multi-location
company headquartered in the east. 

For anyone intent on saving the most energy with fluorescents - use the
electronic instant start ballasts. The rapid start ballasts have a small
resistance heater used for starting the lamps which also stays on for as long
as the lamps are on. [ FYI - Although I have not heard of them used in the
aquarium field, there have been some compatibility issues (read premature
failures on a large scale) with the  3" U-bend T-8's normally used in
industrial 2'x2' fixtures when mated with instant start ballasts. To my
knowledge this has not been the case with straight lamps.]

Ron Lane

Which T8 bulbs to buy?

by (G.Tong)
Date: Sat, 30 Dec 1995

>I recently got four electronic balasts (for $24.95 each) that can run 48
>inch, 36 inch, or 24 inch T8 bulbs.  I had hoped to find plant bulbs in 48
>inch and 24 inch lengths, such as gro and sho or gro-lux in the T8 size,
>but the electrical supply companies in Jackson, MS have not been able to
>find any in their catalogs.  Somewhat of a bummer after all the talk
>recently in this mailing list about how the T8 bulbs are better.  Does
>anybody know of a manufacturer who makes T8 plant bulbs?  If not, what T8
>bulbs are people using?

1. Hie thee to a lighting store (commercial probably) and find T8s with a
high kelvin and good CRI (color rendering index). I'd say get at least 5100
Kelvin and 80% CRI. GE's SPX lamps go higher than 5100 Kelvin in the
four-foot lengths; same with Sylvania.

2. I believe many if not all of the specialty aquarium lamps (PowerGlo,
etc.) are T8s.

3. My local GE store says the Aquarium/Plant lamps they sold have been
discontinued for inefficiency. Too bad because they had CRIs of 100 and
7500 Kelvin for a fraction of the cost of specialty aquarium lamps.

Greg. Tong
San Francisco, CA, USA

"Every infinity is composed of only two halves."

Which T8 bulbs to buy?

by (Jay Bickford)
Date: Sat, 30 Dec 1995

>From: krombhol-at-felix.TECLink.Net (Paul Krombholz)
>Date: Fri, 29 Dec 1995 22:18:46 -0600
>Subject: Which T8 bulbs to buy?
>I recently got four electronic balasts (for $24.95 each) that can run 48
>inch, 36 inch, or 24 inch T8 bulbs.  I had hoped to find plant bulbs in 48
>inch and 24 inch lengths, such as gro and sho or gro-lux in the T8 size,
>but the electrical supply companies in Jackson, MS have not been able to
>find any in their catalogs.  Somewhat of a bummer after all the talk
>recently in this mailing list about how the T8 bulbs are better.  Does
>anybody know of a manufacturer who makes T8 plant bulbs?  If not, what T8
>bulbs are people using?
>Many thanks in advance,
>Paul Krombholz                  Tougaloo College, Tougaloo, MS  39174
Hi Paul,

I found some T8 bulbs from Philips that look promising for a plant tank. The
part number for the 48" length is F32T8/TL850. It is a full spectrum lamp
with a color temp of 5000K, which is what you need for a plant tank.
Grainger sells them for $4.64 each.(Their stock #5U861) A real bargain!
Unfortunatly, that same bulb is not available in a 24" length, at least not
from Phillips. I think Karen Randall is using GE lamps. It may be that they
offer a suitable T8 lamp in the 24" length.

I haven't switched to T8 lamps yet, but I plan to at my next scheduled
relamping in about 6 months. 


Jay Bickford

Fort Smith, Ar.

T12 Electronic ballasts

by (Neil Frank)
Date: Fri, 17 Nov 95

 G.Tong says
>> have never seen a T12 electronic ballast but I troll the
commercial lighting stores and they don't sell them. Hence my post, because
one wouldn't drive T12s with an electronic ballast designed for T8s..<<

Valmont Electric makes an electronic ballast called the Ultra-Miser. They
have models to drive many different wattages of T12/RS and T8/RS bulbs.
Their number is 1-800-533-7290
Visit the Aquatic Gardeners Association home page

Tank Lighting?? Help

by Thomas Murphy <>
Date: Wed, 23 Oct 1996
Newsgroup: rec.aquaria.freshwater.plants

A few suggestions:

If you are building a hood, you may want to use an electronic ballast
with T8 bulbs.  While a bit more expensive to start with, this setup
would be quite a bit more efficient, and produce less heat, than the
standard shoplight setups.  The most commonly available electronic
ballasts for 48" T8s are designed for F32 bulbs, which are not
compatable with the F40s normally used in aquaria, such as vitalights
and tritons, but F32s are available in 4000, 5000, and 6000 K bulbs at
reasonable prices from good commercial/industrial lighting stores, and
places such as Grainger.  These lighting supply sources should also be
able to set you up with a 3 bulb electronic ballasts for F32T8s for
around $30.  Check out the info on Motorola's ballasts (do a search for
ballast at for some pretty
good information, and to get the model numbers in case your lighting
supply store needs to be able to order your ballast.  

One more thing, when using electronic ballasts, the reflector does not
need to be grounded, with the cheaper conventional ballasts the
reflector needs to be well grounded and within .5 in of the bulbs.

Good luck,

Blue Light

Date: Fri, 14 Feb 1997

Subject: Blue Light

> There has been some
>suggestion that actinic lamps will help maintain red coloration in aquatic
>plants....anybody tried this?

I've just started experimenting with some new 6500K T-8 bulbs (Sylvania)
mixed with my 5000K GE SPX50's.  I did it mostly because I liked the very
clean "sunny" look it gave the tank.  I have found though, that the R.
macrandra, which grows well in all my tanks is _much brighter red than in
the other tanks.  It's not just that it looks brighter because of the light
color.  If you take a piece out of each tank and hold it side by side, you
can see a big difference. (both look perfectly healthy, however)  I like
this combination enough that I've switched my other tanks over so they are
all about half and half each type.

I have _not_ seen any noticeable difference in red Crypts, although that
would take longer to show up in any case.  I have some Ammania in one of
the tanks that I just swqitched over, so I'll be keeping an eye on this to
see how it responds.  The copper in my tap water precludes my use of
Ludwigia sp., so I won't be able to report on them.

Karen Randall
Aquatic Gardeners Association

Plant Lighting

by Davis & Lanelle Chastain <chastain/>
Date: Mon, 24 Nov 1997
To: eriko/

I'm responding to your FAQ request:
I am just setting up a new tank, 75gal, so I cannot tell you yet of the
success.  I do want to let you know that there is a new product out by
Philips (who I work for) that I am going to use.  It's called the Advantage
T8.  I'll be using 4' 50K.  The specs are great, so I am confident I'll get
good results (as long as all other variables are under control!).  As a
comparison, here are the specs of an F40C50 compared to an
F32T8/ADV850/ALTO [the ALTO is our low-mercury feature, irrelevant to plant

			Initial	Design		Lumen		CRI	Life
			Lumens		Lumens*	Depreciation
F40C50			2200		1915		13%		92	20,000hrs
F32T8/ADV50		3200		3050		5%		86	20,000hrs

*Design lumens is lamp lumen at 40% rated life.

As you can see, using the T8 (with an electronic ballast) will give 45%
more light, with a minor drop in the CRI, better maintained lumen levels
(and less energy, 32 watts vs 40 watts).  So, without sounding like a sales
rep for Philips (which I am), I think this will be an interesting product
to try.  I'll keep you posted on the results.

Perhaps I will see you soon at the next GSAS meeting.
Davis Chastain


by "G Tollefson" <g.tollefson/>
Date: Thu, 19 Nov 1998
To: <erik/>


I found the article by Ronald Wosniak very helpful and interesting.  As a
lighting engineer I thought I would add a couple of comments that may
enhance the understanding of this interesting lighting issue.

First of all, T8 fluorescent lamps typically produce a significantly
improved quality of light over the standard T12 lamps (e.g. cool white or
warm white) that we have been using for nearly 50 years.  T8s produce a
fuller, broader spectrum of light. For living space questions, they tend to
be better in color rendition than the bluer cool whites or the yellower
warm whites.  People tend to like the quality better.  Therefore, I can
assume that they are better for aquariums as well.

Secondly, Ronald mentioned the operating costs of lighting as part of his
analysis. There is a couple of features of the T8s and electronic ballasts
that he failed to mention.  T8s are inherently more efficient than T12. 
Plus, the ellectronic ballasts will operate the lamps in a more efficient
manner than the traditional (heavy) magnetic ballasts.  This serves to
reduce the operating costs.  In fact, they operate more efficiently than
even the rating on the tubes themselves.

Let me give you some numbers.  Most T8s are rated at 32 watts each
(compared to 40 watts for T12s).  An electronic (2 lamp ballast) is rated
at about 3 watts (compared to magnetic ballasts at about 13 watts).  Common
sense would tell you that two lamps and a ballast would consume about 67
watts.  In fact, some lamp/ballast combinations actually used less than 60
watts.  That is a significant saving over the 93 watts of the more
traditional T12/magnetic ballast combination.

The purchase price of T8s and electronic ballasts are usually higher than
the standard equipment, but when these lamps are burning 12 hours per day,
seven days per week, the operating costs become the driving factor as to
the financial decisions of which system to buy.  It is cost effective to
use the T8s with electronic ballasts.  When you consider they give a better
light, it really is a no brainer.

The cost analysis wasn't exactly clear from Ronald's paper but it appears
to suggest that two T8 lamps and one ballast consume 90 watts.  This is
incorrect.  It should be 60 watts instead.  This makes their cost
effectiveness even stronger.

An added benefit of the T8s is that they typically degrade (reduce light
output over time) at a slower rate and to a lesser extent than T12s.  This
means that they don't have to be replaced as often to ensure that they
maintain the proper light output.

Garry Tollefson

Phillips T-8 80 series

by "Adam R. Novitt" <novitt/>
Date: Tue, 22 Dec 1998

After a long discourse on the ADA list I discovered that my Phillips TL850
32w T-8 lamps compare favorably with the $32 ADA lamps.  Check out the
spectral spread at the 850
(5000k) is the last colored chart.  Big spikes at 425nm and 625nm locations,
along with a wad of green for CRI.  At about a 1000 lumens/watt they are
very efficient, even for T-8s.   I bought mine for about $5 per.  CF and
other T-8 info is at  and
specific 32w 4' info on the 850 is at
Therefor the PAR is really good?

BTW, I'm totally happy with them.  Just a suggestion for anyone considering
the moce to T-8s.

T-8 lighting

by "wayne jones" <waj/>
Date: Fri, 23 Jul 1999

>>In the aquarium specialty market we've
had 40 watt T-8 bulbs for a long

>Yes for $20 or more per tube.  No

I first started using GEspx50 T8 lamps
with high light output ballasts about 2
years ago. I started out with 4 lamps in
a 90 gallon tank and then later added 2
more Philips 850s. So far I have not
changed any lamps and I have not noticed
a decrease in plant growth on the
contrary things seem to grow better than
ever. These lamps maintain over 90% of
their initial lumen rating over the
rated life of the lamp so as long as
their spectrum doesn't shift I think I
should be able to use them until
failure. The rating is 24,000 hours for
a ten hour start. However, I use instant
start ballasts so this reduces the lamp
life to about 18,000 hours and I also
use high light output ballasts and
supposedly this will further reduce lamp
life to about 15000 hours. Therefore I
expect that my lamps could last as long
as 4 years. The cost of the lamps is
under $6 Canadian so my yearly cost
could be  about $9 Canadian. The yearly
hydro cost of operating this fixture is
about $70 Canadian per year. I have
heard of people changing 4 $30 lamps
twice a year. I could operate three
fixtures including the electricity for
that price. So just how much better can
aquarium specialty lamps be?

T8 electronic ballast wiring

by Dan Dixon <dandixon/>
Date: Mon, 07 Feb 2000

David Papas at wrote:

> Hello all! I've just begun a foray into flourescent fixture building, and
> I've come across a small quandry regarding the wiring diagram present on the
> label.  The ballast in question is a 4 lamp electronic ballst. Thus, from
> the left of the ballast are the black and white power leads and two yellow
> wires. On the right there are two pairs of red and blue wires, respectively.
> My understanding from the 2 lamp ballast diagrams I have seen in the past is
> that each red and blue wire pair connects to one lamp a piece, with one wire
> in the pair connected to one pin on the lamp. The digram for my current 4
> lamp ballst show these wires connecting 1 to a bulb and, just before
> connection, splitting into 2 wires ( one for each pin?). I figured from all
> the talk I've seen in the past regarding custom fixtures someone here has
> dealt with this scenario. What would be the best technique to get this thing
> wired?
> Thanks!
> - -Dave Papas

If you are using the bi-pin "tombstone" end connectors, there are usually
four push-in wire connector holes, two for each pin. The left pair of holes
go to the left pin; the right pair go to the right pin. Just put a short
jumper wire between the two pins using the two inner holes. A red or blue
wire from the ballast is then plugged into one of the other holes. E.g.:

    |           |
    |           |
    |           |
    |           |
    |           |
   | O  O===O  O=====================(red or blue)

(the "===" is the jumper)

Each yellow wire then connects to the opposite ends of two red- or
blue-wired lamps. To get one wire connected to four pins, you can use a
jumper between the pair of tombstomes, like this:

     ___________             ___________
    |           |           |           |
    |           |           |           |
    |           |           |           |
    |           |           |           |
    |           |           |           |
    |___________|           |___________|
   | O  O===O  O=============O  O===O  O=======(yellow)
   |_____________|         |_____________|

Dan Dixon
(not a licensed electrician...use of above instructions may void your
homeowner's insurance :)

36 inch lighting

by zxcvbob <bob/>
Date: Thu, 20 Jul 2000

Bob Dixon sez:
> My local Home Depot carries a limited selection of cool whites and 
> plant bulbs in 36", 30 watt.  All of them are T-8.
> Speaking of which, that confuses me.  When folks started talking t-8, the 
> idea was that you could get more light with the same power consumption.  Now 
> that 48" t-8s are everywhere, they are reduced to 32 watts.  They do put out 
> a little more light than a standard T-12, but I have been told I have to 
> re-ballast my fixtures to run them.  What kind of deal is that?

"T-8" is a size designation for the lamps.  It means the lamp is
tubular, and 1 inch in diameter. That's all it means.  The smaller
diameter is inherently more efficient because there is less restrike
in the fixture.  The 48 inch T8 lamps are designed to run at
significantly less current, but higher voltage, than the old F40T12
lamps, so they need a different ballast.  These new F32T8 lamps
produce more light per watt than their F40T12 (now, F34T12)
counterparts, and they are cheaper too!  There is a 36 inch version of
the new technology lamps, F25T8, that will operate on ballasts
designed for F32T8 lamps.  Unfortunately, there are also F30T8 lamps
that are compatible with the old style F30T12 lamps.  The F25T8 and
F30T8 lamps look the same, but they are not compatible.  If you put an
F30T8 lamp on a ballast for F25T8's, it might light but it will be dim
because it is operating on too low current.  If you put an F25T8 lamp
on a F30T8 ballast, the ends will get hot but the lamp will not light
because the voltage is too low.

I reballasted some of my 4' fixtures to convert them to F32T8 lamps
because I was tired of those dim 34W lamps, and real 40W EPACT
compliant lamps were too expensive and hard to find.  I recovered
about half of the cost of the ballasts just on the relamping costs of
the first set of lamps ($3 each, versus about $10).  Then there's the
ongoing energy savings, and recurring savings each time I replace the


- -- 
"We tend to scoff at the beliefs of the ancients. But
 we can't scoff at them personally, to their faces,
 and this is what annoys me."
- --Jack Handey

More T8 Stuff

by busko/ (Ivo Busko)
Date: Mon, 7 Aug 2000

With all this talk about T-8 ballasts, let me just add a warning:
there are out there electronic ballasts that can drive 1, 2, 3 and 4
lamps. The 4 lamp models have always ballast factors < 1. Three lamp
models can be found with ballast factors as high as 1.2. So it is 
possible to have a 3 lamp configuration that produces as much ligth as
a 4 lamp one, by just replacing the ballast. If one is designing a
lamp fixture from scratch, it just doesn't make sense to use the 4 lamp

- - Ivo Busko
  Baltimore, MD

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