Hi, recently acquired a 29 or 36 gallon octagon that has a perfecto 18 1/2 inch hood light. I'm guessing it's old because the fixture is 2 "screw in type" bulbs. Not a regular flourescent tube. Do they still sell the type of screw in bulb I would need for a fish and plant aquarium or should I just pitch it and find a new 18" that takes a flourescent? Let me know if you need any more info or a pic. Thanks a ton