Make sure to record whether he pooped/peed before weighing, because doing so can make a hedgie lose 25-30 grams. If you weighed him before potty the first time, then after the second time, that could also cause the 30 gram change.
If that's not the case and he hadn't gone potty before weighing, I still doubt it's anything to worry about. Sounds like he's definitely eating a more healthy diet now, which will likely put some weight on him. Keep an eye on his body shape: you want to see ( ) or ||, not (----) (body wider than length) or ) (. As the others said, though, he's likely to be gaining from the good food and it will taper off as he gets more settled in.
Does he have a wheel, by the way?
If he's drinking all his water, make sure you fill the bowl often. How big is the bowl? Will he need a bigger one, just to make sure he doesn't run out overnight when you're asleep and can't check it?