Review on Roxin 5W 7W 13W UVC Aquarium Green Clean Light Algae Bloom Clear Lamp - Aquatic Water Cleaner for Pond Fish Tank, Sump, Swimpool - Waterproof UV Sterilizer by Katherine Treadwell

I had to turn it off after two days because it was working too well! This is on an uncoated filter. This is a 54 gallon aquarium that is heavily planted and stocked and powered by a canister filter and sponge air intakes. The reservoir sits under my covered outdoor patio and receives only natural sunlight. Algae is one of the biggest problems I face when working in open tanks. After getting this aquarium UV light I've been using it for at least 48 hours straight and no new algae has built up in the aquarium (because it grows fast on the walls so I clean it often) but algae did build up on the Gravel and the plants turn white because they die! I've turned it off for now because I need seaweed for the new fish coming out this week. DO NOT EXPOSE FISH TO LIGHT OR THEY WILL DIE. That's what the instructions say. They are best placed in swamps or large filters. It says submersible, but I haven't tried it yet. I will if/when I build my swamp. This thing delivers what it promises. I enjoyed reading the reviews and instructions!