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[Owzi]

I would consider leaving it on. 16deg sounds to cold to me. Even though temps in the lizards natural environment may get that low, often lizards find little micro climates (like between rocks) that stay warm overnight.

Or you could try getting a heat cord/mat just for nights to provide a slightly warmer spot after the basking lights go off?

That said, im no lizard expert. Had a pair of Central Beardys survive happily for 14 years with heat provided 24hrs.