Originally Posted by RuslanJamil

I am not sure what PL-L actually stands for but it is used by Philips to denote a type of fluorescent tube. The Osram equivalent is Dulux L. Some people call them Power Compacts. There are several wattages available but the common ones for aquarium use are the 36 W and the 55 W. The 36 W bulb is 18 inches long and is a good fit for 2 foot aquariums. As mentioned earlier, I use 2 bulbs for my 2 foot tank. The first picture shows my light casing and the various 36 W tubes. The second picture is a close-up shot of the ballast that is used in the casing and the ballast is sold separately in some LFS. Would be a good candidate for a DIY project because minimal wiring is needed. Third picture includes an electronic ballast that can drive 3 or 4 18 W tubes which I have been planning to incorporate in a DIY project.