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We've got a discussion going in chat on this, and I'm confused now! So... can someone help clear this up?

When using compact fluorescents, there's a number, say, in the case of the bulbs I'm using on my tank, 23w = 100w. Precisely, to quote the manufacturer]http://216.86.216.207/minitwist.html[/link], it says, "100 watt replacement using only 23 watts." Similarly Gone_Troppo asks about [link=these bulbs in his post in the same forum... in which 15w = 75w.

The discussion we have going is on which number to follow. Ages ago when I started my 20 gallon long, I asked a lot of questions on this and I swear I was told you follow the lower wattage number; that's what I've been following these years.

Simply on reaction of plants I've had in my tank, I think that what I was originally told is correct (and, of course, I can't find my original post). Otherwise, I think I'd be able to grow ANYthing under 10wpg!

In any case, this discussion has gotten me confused, someone help! What number do you follow?

~Meow. Thus spoke the cat.~

well i know some of the lower end screw in compact flourescents like the ones for around the house are rated in comparison to incandecents. i was actually thinking about this the other night when i saw some at a hardware store. when i asked the electricain about it he said the efficiency gain is over incandescent not standard flourescent. i guess the gain over standard flurescent would just use and estimation some where in the middle.

*click *flash *click "whered he go???"

I agree, a 15w flourecent bulb has similar output to a 75w incandescent bulb, but only uses 15 watts.

When calculating WPG, use the lower number for flourecent bulbs.

*edit* And don't forget to not go over the manufacturer's recommended wattage for the lighting unit!

Not to get off subject, but what will happen if you do go overboard?

><> ~=!Vote Today!=~ <><
-----> View My Dragons <-----

well if its a screw in one like the ones in the link a few things can happen. one thing would just be that the bulb wouldnt lite. another would be, that the gfci plug would pop and shut off. but i think the worst would be that the wires would heat up and melt, which could cuase a fire.

i am a self proclaimed expert at frying electronics.

*click *flash *click "whered he go???"

Hi,
This can be an interesting problem.
From very early in our lives we begin to understand
the differences in the amount of light given off by
a 15 watt incandescent bulb in relation to that of
a 150 watt bulb.
We also have come to realize the difference between a
18 watt fluorescent and a 40 watt fluorescent bulb.
Now, with the advent of the screw-in fluorescent bulb
and the energy conservation advantage to them,
manufactures are now telling us that the bulb is
75 watts but consumes 15 watts.

From days or yore, we have used the Watts per
Gallon (WPG) concept when trying to determine what
light(s) we want to use on our aquariums to grow
different kinds of plants. We even have grouped
our plants into low, medium, and high light demand
plants.
The generally accepted groupings are:
1-1.5 wpg is for low light demand plants, 2-2.5 wpg
for medium light demand and, and 3+ wpg for high
light demand plants.

Light bulbs were/are measured by the amount of power
the bulb consumes to generate the resultant light that
we see. However the amount of light that strikes
the object is measured in Lumens.
Because of the types of light and the different
phosphors and improvements over the years in the
various phosphors used in fluorescent lights, we
cannot say the one Watt equals one Lumen.

See this site for more detailed definitions and a chart
of various bulbs and their overall ratings:
http://www.aquabotanic.com/lightcompare.htm

An interesting way to compute how much lighting you should have, or do have,
can be done by using the following site and doing the math:

http://faq.thekrib.com/plant-lighting.html
In using the information in this example, to grow medium to bright light plants,
with a photo period of 10 hours (lights on for 10 hrs/day), I would compute:

Tank length x width (26x12 = 312)
Then times the distance from the surface to the top of
the substrate (10) would be 312x10 = 3120.
To grow moderate to bright plants I would multiply
3120x 0.18 = 561.6.
Lastly, multiply the watt hours by the photo period
which is number of hours the light is on. This number
is generally 10-12.
For my tank, the lights are on for 10 hrs/day therefore
561.6/10 = 56.16 watts, so my 96 watt bulb is way more that sufficient
for just about any plant I might select.

Personally, I still find that working with the number of watts per gallon still works,
as long as you use the same base for comparison.
That is the equivalent incandescent power.
If the bulb is rated at 75 watts incandescent,
it makes no difference how much energy it saves,
use the higher number.

Additional Ref:
http://www.theledlight.com/lumens.html

Frank




-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

good info as always frank. but one comment/ question. i thought the wpg rule was base on flourescent light not incandescent. but the larger rating # is watts of incandescent light. so how would we go about finding the output of standard flourecent light. wouldn't we have compare lumen output?

*click *flash *click "whered he go???"

I'm so confused over this now... I mean, while I'd love to say that my tank has 10wpg (as it would if I truly were to go by the higher number)... yeah, I dunno. I give up. My brain doesn't work this early in the morning.

~Meow. Thus spoke the cat.~

Hi,
The WPG "rule" created using the incandescent light and
as the ads for the compact fluorescent lights show, it still is.
It is just that fluorescent lights have now become
THE light to use on freshwater aquariums. But fluorescents
used to have the same marketing hype that the newer
compacts now have. With newer solid state ballasts, there
are still the occasional ad that says that these lights
(the fluorescent tubes) consume less electricity than xxx
and give off more light.

In a sense, we have now skipped the incandescent light
while keeping it as a "understood" and now run directly
on the fluorescent bulb for the wpg.
We don't care, now, what the incandescent equivalent
is, instead we use the rating on the fluorescent bulb
We now look at the fluorescent bulb label and accept
the 40 watt, 55 watt, 96 watt, or whatever, and use
those numbers in computing the wpg
(total the watts/capacity of the tank = wpg).

Actually many prefer to use Lumen's instead and go
for the highest lumen rating bulb.
The number of lumen's that the bulb gives off is what
is important and what actually "hits" the plants at
the surface of the substrate.
The problem is that most manufacturers do not state
what the lumen rating is of their bulbs.
When was the last time you saw on a package or in an ad
"1025 lumen," or do you see 100 watts? To find out the
actual lumen rating of a bulb you have to dig into various
catalogs specifically for various light bulbs.

Though not always correct, the WPG "Rule" is still the
most easiest applied, and does get us into the ball park
in plant growth and a pleasing appearance of our tanks.
(not pink, bluish, or yellow, but white).

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

One thing no one has mentioned yet, is the K rating, or the spectrum of the lights. From personal experience, I have used those lights and even bright higher wattages than those, and the thing is, because of the spectrum of them, you will have a massive algae growth in your tank, lol. Yes, I have experienced it!

Now, on the same subject of the screw in PC bulbs, they do make them in the spectrum for aquariums. I have used them in tank lids made for incandescent light bulbs. They work great. They even make them with half or full actinic blue for those nano tanks keepers out there. These do work great on your tanks. Coralife makes them, and they come in 10 watt and 20 watt;


I also have a friend that uses one of these on his sump with macro algae for his reef tank;




_____________________________________________________________

There is always a bigger fish...

Ok I have a question. what is the difference between A Normal bulb for the Aquarium and the Actinic one? Other than it lights up blue. I have the same bulb Acidrain posted about and a second one for aquariums, not the coralife one. but I was just wondering what if any the difference is?

mts.gif" border="0"> I vote do you?
My Tanks at Photobucket

well like you said the actinic is blue. as far as i know it brings out the bright colors and makes your fish almost glo. kinda like a black light but less harsh

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