I thought my uv
sterilizer was helpful in keeping the tank clear and free of disease, it was expensive, high wattage, measured dwell time to where I was achieving level 2 sterilization....it didn't make much of a difference.
I never got diseases...but now that it has been off awhile I still have no diseases. My water is perfectly clear without it being on. I'd say it was a waste of a few hundred dollars.
Sent from my iPad using Aquarium Advice