tony

i have changed my mind and decided to put 2 florescent light bulbs on my 55 freshwater tank. they will be the spiral type instead of the tubes. i will use a 40 watt and a 60 watt to give me a total of 100 watts. that ends up being about 1.8 watts per gallon. is this good to grow plants i dont want to have co2 injections so this is about as high as i can go correct and the light would be unevenly distributed through the tank. there would be a 40 on one side and a 60 on the other. is this ok?? does this sound like a good plan

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sirdarksol

The lighting/CO2 needs are determined by the plants and/or the plants are determined by the lighting/CO2.

So, here's the question:
Are there particular plants that you want, or are you willing to just go with what your lighting can support?

Also, compact fluorescents should be measured by closer to their actual wattage, rather than their equivalent incandescent wattage.
I've actually come to realize that the wpg thing isn't as concrete as some portray it, since different lights have different dispersal qualities, as well as different efficiencies as translated in watts per lumen, but it's a halfway decent start.

tony

i am willing to go with whatever plants my tank can support. and what do you mean that i should go closer to the actual wattage rather than the their equivalent incandescent wattage? so you mean that i would only get 15 watts out of these? that is the wattage that they use

sirdarksol

Precisely.
The idea is that wpg is based on the energy a fluorescent light uses, anyway. Compact fluorescents, I think, produce a bit more light than a normal flourescent of the same wattage, but not much. (this is simplifying, as it has a bit more to do with distribution of light, but we won't go into that)

I just checked, and yep, fluorescent tubes and compact fluorescents produce about the same lumens per watt used.

So, based on this, I would guess that you're going to change your mind on the matter.
(BTW, don't feel bad, I made the exact same decision for the exact same reason about a year ago )

Anyway, no matter what, there should be a couple of plants your tank can support. Java fern, Anubias, and Java moss are all excellent low-light plants.

tony

im still a little confused. i dont understand how i would only get 15 watts of light out of the florescents if it says that they put out 60 watts, even though they may only use 15 watts

lilsoccakid

because they put out 60 watts of incandesent light, not 60 watts of compact flouresent light. they are only 15 watt CF bulbs, which means you have 15 total watts over 55 gallons, which is about .27 WPG

sirdarksol

This is why wpg is pretty pointless, in my opinion. I wish people would go by lumens, which is closer to the true power of the light (still not exact, but closer).

To give you an example, a 40 watt fluorescent tube produces somewhere around 3200 lumens, and a 40 watt compact fluorescent produces somewhere around 3200 lumens, while it would take an incandescent light of over 150 watts to produce the same amount of light.
Metal halide lamps seem to be a bit more efficient than fluorescent, and can handle much more power, which is why they put out so much heat. They also cost a ton.

tony

ok i understand now. thank you. so how many lumens would i need for a 55 gallon tank? i dont want to have co2 injections either

sirdarksol

Okay, I'm still working this out, because I just figured out the problems with the wpg (which does work for fluorescent tubes, which is what most planted tanks use).
But I think...
For what most people would call 1wpg, you're looking at around 3,000 lumens (in the proper spectrum for plants, of course), which pretty close to the equivalent of a 55w fluorescent tube.
If you went with this, you could easily keep Java Fern, Java moss, and Anubias.

tony

so if i wanted 1.8 wpg... it would be 5800 lumens and are you telling me that i can use wpg for florescent tubes??

sirdarksol

Yep and yep.
Have I confused you, yet? Because I'm pretty darn close to confusing myself.
As I said, I'm still working this out.
The short is:
If you're using fluorescent lights of any sort, go by the actual wattage they consume. It won't be perfect, but it will be close enough.
If you're using incandescent, metal halide, halogen, LED, or kerosene lamps, wpg goes out the window.

tony

ok. thank you sooooo much. you saved me from messing up my lighting completely. i think im goin to use a total of 95-110 watts. this will give me 1.7-2 wpg. that should me perfect for low-medium low plants, correct

lilsoccakid

correct

tony

yes!! i got it! thats why i ask you guys before i do anything to my tank. i have you guys approve it so i dont mess anything up lol

sirdarksol

Always a good idea. Like I said, I almost made the same mistake a year ago. If I hadn't asked, I wouldn't have known my error until my plants died.

tony

ok. so what i think i am going to do is use 4 of the spiral florescent light light bulbs. they consume 27 watts and have an incandescent output of 100 watts. so 4x27 is 108 watts. so thats 1.96 wpg. will this work

MrWaxhead

Lumen to watt rating of a spiral compact bulb is about .86 of a t12 which wpg is based on so 4 27 watt bulbs would be 108 x .86 for 92.88 divided by 55 for 1.69 wpg which still should be fine for low to medium light plants.

sirdarksol

Check out the big brains on Brad (your new name is Brad, MrWaxhead )

Yes, somewhere between 1.5 and 2.0 wpg should be good for anything that is low to moderate lighting.

So now we can talk plants:

Crypts are good. I've been having luck with dwarf onions. Water wysteria is really hardy and grows like a weed, but makes a beautiful canopy. I've heard that swords can be easy to grow.

Check out Plantgeek.net and search their plant listings by light level. There will be a bunch of ideas there.