Testing screw in fluorescents

Not too long ago there was a short discussion on the effectiveness (or
lack thereof) of these bulbs. For a recap do a google group search on
"Screw in fluorescent bulbs" One of the points that was brought up was
that the problem may be that the bulbs Richard used were soft whites
instead of 6500K bulbs. Since I have essentially the same setup that he
discussed in his post I decided to try some testing.

Today I went out to Home Depot and bought two 19W 6500K screw in
flourescent bulbs - sadly that seems to be the highest wattage you can
get for a 6500K bulb. What I had in my tank were two 3500K (soft white)
25W screw in flourescents. Since I wanted to see what the difference
would be I removed one of the 25W bulbs and replaced it with the 19W
6500K bulb. It is obviously closer to sunlight since one side of my
tank now has white light and the other has a yellow tint to it (just to
be clear, the side with the 3500K bulb is yellow). However to my eye
the new bulb looks quite a bit dimmer. I guess this is just the
difference between a 25W bulb and a 19W bulb showing up but I'm not
sure which one will be better in the long run.

So rather than going ahead and putting both 19W 6500K bulbs in like I
planned I've decided to leave it half and half for a few days just to
be sure this will be an improvement. For the next few days my tank will
have 19 watts of 6500K light on one side and 25 watts of standard soft
white (3500K) light on the other. As soon as I notice a significant
difference in plant growth (if I do) I'll report the results. I think
it will be interesting to see whether spectrum or total wattage is more
important to plants. Bets anyone?

-Daniel

dfreas wrote:
Not too long ago there was a short discussion on the effectiveness (or
lack thereof) of these bulbs. For a recap do a google group search on
"Screw in fluorescent bulbs" One of the points that was brought up was
that the problem may be that the bulbs Richard used were soft whites
instead of 6500K bulbs. Since I have essentially the same setup that he
discussed in his post I decided to try some testing.

Today I went out to Home Depot and bought two 19W 6500K screw in
flourescent bulbs - sadly that seems to be the highest wattage you can
get for a 6500K bulb. What I had in my tank were two 3500K (soft white)
25W screw in flourescents. Since I wanted to see what the difference
would be I removed one of the 25W bulbs and replaced it with the 19W
6500K bulb. It is obviously closer to sunlight since one side of my
tank now has white light and the other has a yellow tint to it (just to
be clear, the side with the 3500K bulb is yellow). However to my eye
the new bulb looks quite a bit dimmer. I guess this is just the
difference between a 25W bulb and a 19W bulb showing up but I'm not
sure which one will be better in the long run.

So rather than going ahead and putting both 19W 6500K bulbs in like I
planned I've decided to leave it half and half for a few days just to
be sure this will be an improvement. For the next few days my tank will
have 19 watts of 6500K light on one side and 25 watts of standard soft
white (3500K) light on the other. As soon as I notice a significant
difference in plant growth (if I do) I'll report the results. I think
it will be interesting to see whether spectrum or total wattage is more
important to plants. Bets anyone?

-Daniel

Not placing any bets but I'm very curious as to your results. Mine seem
to depend on the plant. I put a 14W 5500K compact screw-in in the hood
of my betta's 2 gallon tank instead of the sunlight I was using, moved
the tank out of the window, and switched the substrate to fluorite.
(The lighting change was because the stem plants were growing sideways
towards the window and I couldn't grow anything in the foreground.) The
previously slow-growing Rotala indica took off, and the foreground
banana lily is no longer losing leaves, but the Mayaca that was doing
very well is now dying. *scratches head*

--
__ Elaine T __
__' http://eethomp.com/fish.html '__

Let's assume for a moment spectrum doesn't matter and there's no great
difference between the worst (soft white) and best (triton) tubes. An
article in the kib says philips tested this and found a 10% difference
in plant growth from worst to best - insignficant.

Twenty years ago in these newsgroups people began talking about
different colors of light and how they affect plant growth. To
this day there is no such thing as the "right" spectrum. If there
was somehow it's evaded the notices of what much by now be millions
of aquarists over two decades. I can believe I'm this dumb but I
seriously dount the collected wisdom of all aquarists here is.

I doubt as well there's any question 80 watts of 2' fluorescent
will give better results than 20 watts of 2' fluorescent light.
Intensity matters.

In _The Optimum Aquarium_ Horst and Kipper note that "any fluorescent
tube light without a reflector should be rejected - 30% of the light
is wasted". Being a cylinder, there's no point in an equal distribution
of light pointing up as down into the tank henct the need for a reflector.

So, a 20W bulb putting out, as an examlpe 1000 lumens will only shine
700 lument into a tank and you'd need a larger than 20W tube w/o a
reflector to get as much light into the tank as a 20W tube with
a reflector.

Now, say you removed that 20W 2' light and put in a single 24watt
screwin in the middle of the tank. More watts, but a simple
test with a light meter in a plastic bag shows that at the ends
of the tank you don't have the same lux or lumens there as you
did with the 2' tube - the tube ligts evenly acros it's length,
the screwin blasts light in a radial pattern and all those spirals
casue strike back - light is bounced around everywhere losing energey
(dramatically) every time it bounces.

So, the problem with screwins is not really that they don't put out
much light, they do, but you just can't focus it and get it down to
the plants leaves very well.

Where screwins really shine (haha) is over small tanks where you can't
put a tube (Elaine, I doubt your Mayace problem is spectum; put the old
bulb back in and see what happens) but my opinion is because they
waste so much light you need to make a more or less continuos strip of
them, ie 4 of them to replace a 2' tube to get the same amount of light
*on the plant leaves" as you would with a 2' tube and at that point
you're wasting so much energy ($$$) and generating so much extra heat
that it seems to me like a very diminished return.





--
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633CSi 250SE/C 300SD | Killies, killi.net, Crypts, aquaria.net
1970 280SE, 72 280SE | Old wris****ches http://watches.list.mbz.org

Interesting. And almost certainly correct - I figured there was a loss
from the shape but didn't think it might be as significant as you
suggest. I think I will continue with the test for now just to see what
happens. I don't think I'm going to change to tube lighting - mostly
because I'm only growing low to mid light plants in this tank anyway
but I may start thinking about ways to modify my current setup to get
more of the light into the tank. Deffinately something to put some
thought into.

-Daniel

In article .com,
dfreas wrote:
Interesting. And almost certainly correct - I figured there was a loss
from the shape but didn't think it might be as significant as you
suggest. I think I will continue with the test for now just to see what
happens. I don't think I'm going to change to tube lighting - mostly
because I'm only growing low to mid light plants in this tank anyway
but I may start thinking about ways to modify my current setup to get
more of the light into the tank. Deffinately something to put some
thought into.

Well, it's a point source of light, not a strip, so, look to
exampled of other point sources of light. For example, metal halide
bulbs. They use either batwing reflectors or pendants.

I found some cheap ($1) reflectors at a salvage place. Combined
with cheap ($1) 11W screwins from "Dollorama" they make, well,
a reasonable $2 light for a small tank:

http://images.aquaria.net/hw/lights/pendants/cheap/

For screwins in incandescent fixtures about the best I could do
is use the heat and moisture resistant mylar from hydroponics.com
and these fixtures are on my daughters tanks that have crypts
and java fern:

http://images.aquaria.net/hw/lights/screwins/


--
Need Mercedes parts ? - http://parts.mbz.org
http://www.mbz.org | Mercedes Mailing lists: http://lists.mbz.org
633CSi 250SE/C 300SD | Killies, killi.net, Crypts, aquaria.net
1970 280SE, 72 280SE | Old wris****ches http://watches.list.mbz.org

On Sun, 6 Mar 2005 02:38:36 GMT, (Richard Sexton)
wrote:

In article .com,
dfreas wrote:
Interesting. And almost certainly correct - I figured there was a loss
from the shape but didn't think it might be as significant as you
suggest. I think I will continue with the test for now just to see what
happens. I don't think I'm going to change to tube lighting - mostly
because I'm only growing low to mid light plants in this tank anyway
but I may start thinking about ways to modify my current setup to get
more of the light into the tank. Deffinately something to put some
thought into.

Well, it's a point source of light, not a strip, so, look to
exampled of other point sources of light. For example, metal halide
bulbs. They use either batwing reflectors or pendants.

I found some cheap ($1) reflectors at a salvage place. Combined
with cheap ($1) 11W screwins from "Dollorama" they make, well,
a reasonable $2 light for a small tank:

http://images.aquaria.net/hw/lights/pendants/cheap/

For screwins in incandescent fixtures about the best I could do
is use the heat and moisture resistant mylar from hydroponics.com
and these fixtures are on my daughters tanks that have crypts
and java fern:

http://images.aquaria.net/hw/lights/screwins/


For my 2.5 G tanks I use 13W bulbs. Each tank gets half of an
AHSUPPLY 26 watt bright kit. I just build a new hood from rain gutter
parts, I like it so far.


--
Charles

Does not play well with others.

For my 2.5 G tanks I use 13W bulbs. Each tank gets half of an
AHSUPPLY 26 watt bright kit. I just build a new hood from rain gutter
parts, I like it so far.

Seven watter per gallon ought to work :-)

I tried rain gutter too, white plastic stuff. The problem I had is the
heat from the lights (not insignificant) makes it hard, brittle
and over time turns the inside brown. I ened up grabbing a bunhc of
cheap incandescent hood from garage sales, they have a metal plate
to diddipate the heat. You can scavange a bit of the otherwise waster light
if you add some reflector material.

--
Need Mercedes parts ? - http://parts.mbz.org
http://www.mbz.org | Mercedes Mailing lists: http://lists.mbz.org
633CSi 250SE/C 300SD | Killies, killi.net, Crypts, aquaria.net
1970 280SE, 72 280SE | Old wris****ches http://watches.list.mbz.org

Richard Sexton wrote:
For my 2.5 G tanks I use 13W bulbs. Each tank gets half of an
AHSUPPLY 26 watt bright kit. I just build a new hood from rain gutter
parts, I like it so far.


Seven watter per gallon ought to work :-)

I tried rain gutter too, white plastic stuff. The problem I had is the
heat from the lights (not insignificant) makes it hard, brittle
and over time turns the inside brown. I ened up grabbing a bunhc of
cheap incandescent hood from garage sales, they have a metal plate
to diddipate the heat. You can scavange a bit of the otherwise waster light
if you add some reflector material.

I'm doing the same for my 2gal - using the incandescent hood that came
with the tank. I've got the fixture sitting on eggcrate so that the
tank evaporates more water to keep from overheating.

--
__ Elaine T __
__' http://eethomp.com/fish.html '__

On Sun, 06 Mar 2005 05:34:11 GMT, Elaine T
wrote:

Richard Sexton wrote:
For my 2.5 G tanks I use 13W bulbs. Each tank gets half of an
AHSUPPLY 26 watt bright kit. I just build a new hood from rain gutter
parts, I like it so far.


Seven watter per gallon ought to work :-)

I tried rain gutter too, white plastic stuff. The problem I had is the
heat from the lights (not insignificant) makes it hard, brittle
and over time turns the inside brown. I ened up grabbing a bunhc of
cheap incandescent hood from garage sales, they have a metal plate
to diddipate the heat. You can scavange a bit of the otherwise waster light
if you add some reflector material.

I'm doing the same for my 2gal - using the incandescent hood that came
with the tank. I've got the fixture sitting on eggcrate so that the
tank evaporates more water to keep from overheating.


The incandescent hoods that came with my small tanks were pretty much
junk. The fluorescent lights melted holes in them.

the bright kit comes with a metal reflector, so I didn't need to do
anything there. I've only had the first one running for a week or so,
I'll wait to see how it works out. The plastic is PVC, so it will
probably get brittle over time, if too badly or not, we'll see.


--
Charles

Does not play well with others.

On Sun, 6 Mar 2005 03:45:08 GMT, (Richard Sexton)
wrote:

For my 2.5 G tanks I use 13W bulbs. Each tank gets half of an
AHSUPPLY 26 watt bright kit. I just build a new hood from rain gutter
parts, I like it so far.

Seven watter per gallon ought to work :-)



the watts per gallon does sound outrageous, but I don't see it as too
bright. In one tank some dwarf sagitaria does really well, in another
anubius grows about normally (slow), java moss survives, Echinodorus
tenellus barely lives and algae grows, but not too badly. There must
be a scale factor working here, but I don't understand it.
--
Charles

Does not play well with others.