I will be placing an order this week from Amazon for a Hayward Pump / Filter Combo and would like to add a solar cover for the 18' intex pool that I am installing. Are there any differences in the solar covers that would be an advantage like thicker (Higher Mills), Is it better to get a blue one or a clear one? I just always purchased the intex or summer escape versions before but thought I would get some advice from everyone here on since I have limited knowledge on these units ...