im not sure what gallon tank it is, i started of with just a 20 gallon but shortly after bringing him home my uncle decided to buy me a the exo-terra large wide tank not even sure the dimensions ill have to measue it so i dont know if the versa top would work since the top with this cage locks into place. but the cup idea seems it would help. my ex's cousin also came over today and said i dont have enough foil on, had about 50 covered due to his light and heat lamp on the back half but there is maybe another 1/4 i can cover up. and also the (styra-foam) idea seems very inguenios so im going to tinker a lil today and tomorrow and i will let you guys know the results. thank you guys so much all the ideas are awsome and ill probly end up using a combination of these. the versa-top sounds the best just not sure if it would work on my tank