With a budget of $0, you're pretty much screwed.
Plant lights are generally in the 5500K-6700K range, it give a bluer light which replicates natural sunlight. The Energy Saver bulbs ususally have a K rating around 4000K which is a yellower light and doesn't work well with plants. Another factor is lux or lumens, that is the intensity of the bulbs, you need a bulb with high lumens to penetrate the water to reach the area you need the light in. Water stops the blue wavelength faster than the reds and yellows, which is why you need the lumens. The Energy Saver plant lights are still fairly low in the lumen count. In my opinion the best lights for plants are compact flourescents like the ones at www.ahsupply.com.
Most people will tell you that you need X amounts of watts of light per gallon for your tank, as in 1x = 180 w, 2x=360w, 3x= 540w. My take on that is unless your tank is fully planted, as in having a carpeted substrate with different plants interspersed throughout, you really don't need that. You canget by with less wattaged FOCUSED on the area you want to grow the plants in. For example if you have a 2'x2' area of plants in a 28" high tank that need 2 watts of light to flourish*, you can get by with a smaller wattage of focused light (140W) on that particular area, rather that beaming 2 watts across your entire tank. That will give you a grow area taht is appropriate for the plants without having the entire tank overlit. The most natural looking tanks, in my opinion don't have a single flat amount of light over them but have lighter and dimmer areas like sunlight through foliage.
* 24"x24"x28"= 16,128cu in / 231 =70 gallons x2watts=140W
Plant lights are generally in the 5500K-6700K range, it give a bluer light which replicates natural sunlight. The Energy Saver bulbs ususally have a K rating around 4000K which is a yellower light and doesn't work well with plants. Another factor is lux or lumens, that is the intensity of the bulbs, you need a bulb with high lumens to penetrate the water to reach the area you need the light in. Water stops the blue wavelength faster than the reds and yellows, which is why you need the lumens. The Energy Saver plant lights are still fairly low in the lumen count. In my opinion the best lights for plants are compact flourescents like the ones at www.ahsupply.com.
Most people will tell you that you need X amounts of watts of light per gallon for your tank, as in 1x = 180 w, 2x=360w, 3x= 540w. My take on that is unless your tank is fully planted, as in having a carpeted substrate with different plants interspersed throughout, you really don't need that. You canget by with less wattaged FOCUSED on the area you want to grow the plants in. For example if you have a 2'x2' area of plants in a 28" high tank that need 2 watts of light to flourish*, you can get by with a smaller wattage of focused light (140W) on that particular area, rather that beaming 2 watts across your entire tank. That will give you a grow area taht is appropriate for the plants without having the entire tank overlit. The most natural looking tanks, in my opinion don't have a single flat amount of light over them but have lighter and dimmer areas like sunlight through foliage.
* 24"x24"x28"= 16,128cu in / 231 =70 gallons x2watts=140W
