HELP: 2.5 year old twins waking up very early!

We have 2 and a half year old twins who wake up before 6am. It doesn't seem tragic but it's wearing us and their 6 year old sister out.This started a few months ago when we moved them from cot beds to toddler beds. Before then, they would wake up, squeal for a minute or so then sleep until 7:30 or sometimes even 9am! Is there any way we can regain that paradise lost? They now sleep from 7:30 or 8pm until 5:45. They are then tired early in the day and want a nap. We tried to shorten their nap to 1 hour but it just makes them cranky and they still wake up at the same time. I tried a night light on a timer to show them when it's wake up time, but three weeks in it's had no effect. They wake up early, I keep them in their room with the lights out until the night light goes out, and only then do we start the day. It hasn't worked. Any other tips? via /r/Parenting http://ift.tt/2ej3VqD