At about 2 years old our skylight cracked due to a combination of poor materials, poor workmanship, and a hail storm. I replaced it with one made of white lexan. It is fantastic...the heat has been greatly reduced without any noticeable reduction in light vs before. It seems to be the best of both worlds.
Got ours here..
RV Skylights, Square, Rectangular & Round.
'04 GMC Sierra 2500HD, CCSB, D/A, MaxBrake, B&W Companion, Retrax Pro, AR Power Steps
2013 Rockwood 8289WS w/Diamond pkg
1969 Camaro RS/SS Convertible
Dad's old 1968 Empi Imp (recently recovered from under 21 years worth of boxes/dust)