I am a new pool owner.. I have an above ground 18ft round pool... It came with a blue pool cover, but I am not sure if its a solar cover. I will not be using a heater, so I would love to hear opinions on the best solar cover... Some other sites say clear, some say blue/silver ect.. So I am confused... I realize one may heat it up better and one may be better suited for keeping the heat in thru the night.. Thanks in advanced for all your thoughts on this..