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[sxc_celly]

FreeTv - Depends on whether you want him to hibernate or not. If hes just in an aquarium, best not to hibernate as they need to come up on the land to do so. Yes id be putting the heater in now. Hornet i live in brisbane aswell, on the northside, and the temps are already dropping lower than a young turtle especially 4-5mths old, should be allowed. Your little turtle should be above 19deg at all time being that age, as they cannot hibernate due to no fat reserves and they need to be eating to grow. If its too cold, they wont eat and dont have the far reserves, so can actually die from this, so hornet id be watching your water temp too, your only 30mins from me. FreeTv Id be running a heater at 22-26deg like Idheav suggested, and move the tank away from direct sunlight, as this can heat the tank up too high and cause algae growth. Hope this helps!