|Byron ||09-20-2010 01:29 PM |
This may be out of control, let's back up a moment, before you spend unnecessary money and effort only to have to undo it later.
First, your tank; it is 30g and 24 inches (you mention a 2-foot tube) in length (or perhaps 30 inches)? Over this size tank, one full-length T8 tube will be adequate provided it is the correct type (more on this momentarily). The still-too-frequently repeated suggestion of 2-5 watts per gallon does not equate with reality and is quite false. You can get a fuller explanation of this issue in the series "A Basic Approach to the Natural Planted Aquarium" stickied at the head of this section, so I won't go into the details here.
A tube that extends full length across the tank, or close to it, is all you need. The length of tube (measured not including the prongs at the end) is what you look for when you buy a tube, so it will fit the fixture in the hood. Watts is irrelevant, as each length of tube comes in a standard wattage [though some manufacturers now produce tubes in less wattage as energy saving and they emit the same intensity of light] so you needn't be concerned over the wattage. The standard fluorescent tube is T8 or T12; the "T" is the tube diameter, T8 are thinner than T12 and are better light as they are more efficient. Most manufacturers are now moving to T8 solely, they are better.
Once you have the length, look for a full spectrum or "daylight" type tube. The kelvin rating is important, it is the colour of the light. A tube around 6500K is close to the mid-day sun and provides what plants need plus the natural colour rendition of fish and plants. The "pink" you mentioned is due to high red and blue with little or no green; it used to be said that plants grew better under this purplish light, but that has now been shown to be false. Not to mention the pinkish hue it gives the aquarium.
A hardware store will have daylight tubes made by GE, Sylvania or Phillips. If the K is around 6500K, that will work fine. This light will be sufficient for the majority of aquarium plants. Adding a second tube, i.e., doubling the light, is going to mean a higher level of balance between nutrients and light or algae will overtake your tank in no time. I would go with one tube. I have a single 30-inch tube over my 36-inch 33g tank (you can see it in the photos under my "Aquariums") and the plants thrive.