What's everyone's take on UV sterilizers. I've read plenty where they are being sold but I'd like to hear from a practical point of view. I've heard you can run it only during the day with a timer so you don't kill the good bacteria that come out at night, does that sound weird? I'd like to put one in the sump but I don't want to buy one for nothing. Some people seem to swear by them and other don't...
Louise