Questions on switching to compact flourecents

[Riso-chan]

Before I make any changes i need some answers. I was just looking at some ratings for these lights and found that that put out more light than an average flourecent of the same wattage. So how do I figure this, I have a 55g tank, 48 long and 20 high, and those ratings suggest that if i wanted to replace 2x60w I could go with two 11+w. Any thoughts on this? By the way, got 10 plants, 3 cabombas, 3 moneywarts, 2 long sword grass?, and 2 anubias.

 

[yzakj]

I always thought compact fluorescents also had more watts as well as light? I have one for my 20g high tank and it has 65 watts at around 65000k of light. Most of the compact fluorescents I have seen at my lfs are rated at over 100 watts.

 

[Blinky]

Are you sure you're looking at compact fluorescents? PC aquarium bulbs come in several common sizes/wattages - some I can think of off hand are 24" (55W) & 36" (96W). Many fixtures house more than one bulb, for instance I have one that's 2 x 55W (110W fixture), and one that's 2 x 96W (192W). Maybe what you're seeing is the total wattage for the PC fixtures?
Watts are a measure of the electricity it takes to run the bulbs, nothing to do with brightness.
K ratings (6500K etc.) are a measure of the 'light temperature'; the colour of the bulb. To oversimplify it, the higher the K the bluer the bulb, the lower the K the more red it will appear.
Power compact fluorescent bulbs produce several times more light per watt than regular (T12) fluorescents.

For a 55g, 48" planted tank you'll want a fixture with 2 x 55W PC bulbs or more.

 

[Riso-chan]

From Riso-chan

The bulbs are of a 3500k rating and equal to two 60w. They're called slyvania mini-twist daylight extra. 13watts both, and they are the longer strip that I think you're mentioning. It's a bulb with a spiral on the end. I just put them on today and the cabombas were already starting to bend toward them. Even though they're not the standard strip lights, I have a feeling they'll work. I've already read someone else's post about using similar bulbs, but we'll see how things progress.

 

[Blinky]

You may have read one of my posts - I use 6500K spiral compact fluorescents in my 10g hood, but they're screw-ins, designed to replace incandescent lamps.
I assumed you had a strip light, since your tank is 48" long. The PC bulbs for standard strip lights are what I was talking about above, I didn't know you were referring to screw-based spirals.
26W of light on a 55g tank isn't anywhere near enough for plants, especially considering that with spirals you lose a lot of light due to their shape - is there any way you can get more light on the tank?

 

[Riso-chan]

Riso-chan

Well, so far the plants seem to be doing very well. I moved the plants into closer proximity to the lights. These lights put out close to the same
amount of lumens as two 60 watts, by the way. They're made in lower wattage to save energy. Though, I could probably add a third bulb. The plants seemed to have become more green, and one of the cabombas is almost at the top of the water. I welcome your thoughts on this.

 

[djlen]

Riso, if your plants are doing well, great. But I think you are confusing fluorescent and incandescent here. Don't go by the manufacturer's hype on the packaging as to the ratios of the two different types of lighting.
For a 55 gal. tank, you will need two 55watt fluorescent tubes to get the 2watts./gal. ratio you see discussed on the forums. The two 26 watt fluorescents, though they may be 'equal to 60 watts, incandescent', give just 52 watts of fluorescent lighting over your tank. You will require at least double that in a 55 gal. tank to create a 'low light' environment in your tank.

Len