Just to let you know, I had a screw-in PC bulb on one of my freshwater tanks where the water was splashing onto it (there were no sheilds). It did short out and flames came out of it. Luckily, I was at home at the time. I have since learned my lesson. I use a glass canopy under the hood, if I have to, even if it doesn't fit right after that.
Make sure the electrical components are sheilded from water!