Review on 11W-45W AQQA Aquarium LED Lights - Waterproof Full Spectrum Fish Tank Light with Timer Controller, White & Blue & Red Light, Extendable Brackets - Ideal for Freshwater Planted Tanks by Amanda Estrada

The timer function does not work very well. There's no way to set the clock to turn on and off multiple times a day. In order for the light to turn on at a certain time, you need to wait for that time and turn it on. In the event of a power failure, the light will never turn on without manual adjustment. When someone goes on vacation, a power outage can ruin a planted aquarium. The external timer does not work as others have said. I like that it's waterproof and I don't have to worry about changing the water.