So my tank has a built in hood that fits a particular fluorescent light (Aqua one 18W PL). After about 3 weeks of getting to light, I came home to find it off. When I tried the switch it wasn't doing anything. Since the hood also has two small fans in it I new the power was going. I took out the light from its fixture and found that it was brown and looked burnt at its base. The four prongs has this crusty green coating on them. What happened?!?! Then, to save my plants I headed to the pet shop to buy a new lamp. It worked well for a week until the exact same thing happened! what is going on? I don't wanna keep buying lamps every couple of weeks and I need help. I'm pretty sure it's not the globe that's the problem. Please help.