One of the bulbs (I'm not sure if it's the UVB or grow light) is making a loud hissing/crackling sound. I first noticed it last night just minutes before lights off. I'm curious what this noise is and if I should be concerned.
I would replace them , and save the old ones for a emergency spare - water and electricity is always not a good combo- sometimes when a light is getting ready to go out, it will get very bright, or make funny noise - also, be sure your connections to the bulb are clean - UNPLUG IT FIRST - look to be sure the humidity has not created a bad contact connection
hope that helps