The UV lights arrived safely. Poor instructions for use--both in packaging and on website. The lights FLOAT. How to get them to stay down on bottom of pond? The tiny-print paper inside says to put the light inside a filter??!! Never have seen a filter to fit that long bulb. For now, I slid them inside the holes in a cinder block. Not a great solution. Hope the lights do not kill my fish. Follow-up, 2 weeks in: These lights are fantastic! After my old UV lights died, my two fish ponds looked like pea soup. After only a couple days, the water began to clear. Now, 2 weeks in, it is crystal clear. I only have to change my filters every 4-5 days. These lights are not only much less expensive, they are far more effective than 2 other UV lights I've purchased. Even though they float, I would recommend them. I do hope play-it-koi will find a way to sell weights that might be installed at one end so the light stays under water.