Ah, I woud disagree with T8's being better. You will be limited to 17 watt bulbs.
Your tank is 19" tall, so everything I have researched suggests a double T5 light would b better than double T8's.
I mentioned the glass lid because a double bulb canopy would no longer fit over your current lid. Glass seems easier as you have more space to sit the canopy on. Perfecto brand has some, but may just search google fpr glass aquarium lids.
I find LED
's too expensive, in comparison to T5's, so I haven't looked into them.