Update: Electrical Safety
Be sure to seal your bulbs and connections with aquarium-safe silicone or sealant, especially if the bulb is down inside the sump. You can't see it, but there will be tiny amounts of salt spray that will build up where you screw the bulb in, and also where you made electrical connections. When the buildup gets thick enough, it will short out and blow a fuse. So each time you replace a bulb, re-seal it. You should be able to pour water over it without it causing a problem.
Be sure to seal your bulbs and connections with aquarium-safe silicone or sealant, especially if the bulb is down inside the sump. You can't see it, but there will be tiny amounts of salt spray that will build up where you screw the bulb in, and also where you made electrical connections. When the buildup gets thick enough, it will short out and blow a fuse. So each time you replace a bulb, re-seal it. You should be able to pour water over it without it causing a problem.