I have two tzitziot, one for during the day and one to sleep in at night. When I wake up in the morning I take off my night tzitzit and put on my day one and make a bracha, is this allowed? And should I make a bracha when I put my night tzitzit on before bed?
This is fine. Because you change the tzitzis for the day, you make a new beracha on the tzitzis that you put on in the morning.
The custom of sleeping with tzitzis is mentioned by halachic authorities in the name of the Arizal, though there is no obligation to do so, and many (most people) do not sleep with tztizis on. It is recommended to do this “bli neder” – without accepting the practice as a “neder.”
One does not recite a beracha on wearing tzitzis at night.