Best solar pool cover

I have had several pool covers over the years, blue, blue and black, clear, clear with diamond shaped bubbles. Last year I purchase a "Gold Series" solar cover. It is blue on the top with a reflective good metallic layer that faces down. This cover is by far the best cover I have ever owned. It's high quality but more importantly I have 5-7 more degrees in water temperature then I have ever had. In July I had to take it off the water was so warm. Very pleased.