13W Aquarium UV Sterilizer for 70-200 Gallon Fish Tank Light Aquarium Algae Clean Light Green Killing Machine Algae Remover

This should be absolutely clear in the instructions, and either it’s not, or people just aren’t reading them: Do not put this in the tank with your fish or other animals. It will kill them. You’re not even supposed to look at the light. It can damage your eyes, and possibly your skin, too.I put mine in the filter, which hangs off the back of the tank, and is black, so it kept the light away from everything but the water flowing through it. I wasn’t sure how well it would work there, since the water only gets exposed to the light for a short time, but I had the greenest water I’ve ever seen, and in just a few days, it was crystal clear, and no fish or live plants were harmed.That’s why we read the instructions and the reviews, people.I can’t speak to how long it will last, because I turned mine off after the water cleared. It’s been weeks, and the green water hasn’t come back, so there’s no need to run it all the time.