Originally Posted by darkxrose
Er my tank is 30" long (20 gallon long)
but the tube in my lighting fixture is only 24" long
Okay well that changes everything, you definitely can buy double-tube fluorescent strip lights for a 30" tank. (The tubes are always shorter than the strip itself, that is normal...when you buy the strip, you buy it by the total length of your tank. If/when you need to buy the fluorescent tubes themselves, you by it by actual length of tube.)
If you can find a 30" hood with a double-fluorescent tube built in, go for it! Otherwise, you are "stuck" with a versa-top and something like this
The double-tube will be a little bit wider. Whether that would make it "too wide" to fit over the clear part in your current hood is not clear to me. If you have a really good LFS
that might have a double-tube strip in stock, you could always go and measure its width and compare it to the size of the window in the top of your hood.
And thanks for the compliment on the tank...it is a work in progress (midway through a new aquascaping) and currently houses about a dozen Yellow Shrimp, one Crystal Red Shrimp (the lone survivor of a shipment gone bad...long story), and some blue ramshorn snails.
A T5 system like thincat suggested is also a possibility, and a great one, if you can afford to spend the money on it. Though honestly, with a double fluorescent strip running you probably $55-60, then spending $99 on a simple T5 isn't really all that much more. And it would give you way more light; even a simple double-bulb T5 is going to be 48W of light. Worth considering if you can afford it!
Wow, I just saw this fixture
for a mere $49.95. Now the actinic bulb won't do anything for your plants, but if you could pull that bulb out and replace it with a second 10,000K standard T5 bulb, that would give you 36W. Nice amount of light for the money spent. This one
for $99.95 gives you 48W designed for freshwater plant growth. Good stuff!