quaanxoawn

@quaanxoawn, at work, I develop roof coatings. I check the temperature on different colors. And aluminum color doesn’t reflect that much heat. White does. About your whit lid, White plastic alone is not opaque enough and let light it. And you’ll get algae and other nasties that cause root rot If you add extra coat on top of aluminum foil - opacity will be okay. I have tried this on clear roof window. The building was a bit darker. Our summer get 40 degree hot and people rather spend money on lighting rather than a/c. Or you can put a white panel on top of your aluminum sheet. I think out door hydro is great. Good luck and happy growing.

@Med_in_Tropic, Original color of the lid is white and it lets light get inside, can cause root rot :(

If you feels the solution is too hot, painting the lid white helps.