Yes, regular epsom salt from the drug store, just make sure there aren't any added fragrances or anything.
Do you feed freeze dried or frozen bloodworms? And how many/frequently do you feed them? When you feed pellets, how many do you feed? SBD usually results from bloating, so I'm trying to figure out what sort of feeding changes you'll want to make to keep this from happening again.
IF they're freeze dried bloodworms, I would feed no more than one per week, just as a special treat. The primary diet should be pellets, one or two fed twice per day to allow him ample time to digest. I'd skip out on the flakes, they're not as nutritious and they contaminate the water faster.