planted discus tank

Question
Dear Doug

I am about to set up a 60l 24h 19w (inches) planted discus tank. I intend to do this over a slow period and not introduce the discus until the tank is well setablished. I will introduce other suitable fish for discus in the ealy stages. My main question is due to lighting. For cost reasons and consideration of the discus I have decided to go for florenence lighting and will use four flourance tubes. I am however need some advice on what lighting to use. What is more important the watts or the K scale in lighting the tank. I realise that being a deep tank that the lower plants my will not recieve that much light. I will therefore plant to plant low light requirement plants. Any advice on lighting will be helpful

I also will have undergravel heating and co2 supplement.

Thanks Andre

Answer
When considering the lighting that you are going to use, both the number of watts and the Kelvin temp are important. For virtually any planted aquarium, especially a deep one, you need at least 2 watts per gallon. If you use more than that, you may want to consider adding a bit of shaded area to allow your discus some reprieve from the light.
As far as the Kelvin temp is concerned, this is simply a way of telling you what color light is emmitted. As I'm sure you know, plants use mostly yellow to red light (5500-6500K) in photosynthesis (and reflect green light, hence their color). So, you want to avoid using green light. Depending on the plants that you use, you may want to add a blue light as well. Red plants utilize more blue light than green ones. (up to 10,000K)
The undergravel heating is an excellent idea. You may also consider a gravel supplement. Laterite is an iron supplement commenly used as gravel or in the gravel. Here's a simple rule of thumb, if the plant is rooted in the gravel, it must uptake iron from its roots. If it can float, attach to a rock/wood it can take up iron directly from the water.
Hope this helps,
Good Luck