I HAVE used Epsom Salt in many enemas. Epsom Salt and soapsuds together in the same enema is what I use when I want a very thorough purge.
I have NEVER taken it orally, and have no plans to do so.
I am not familiar with sodium sulfate, but it doesn't sound like anything I want to mess with.
With Epsom Salt, some things you have to be careful of:
1 Round ONLY! Your kidneys CAN'T TAKE IT twice that close together.
After one round, get your clear return with SOAPSUDS ONLY.
No more frequently than every 2-3 months!! No excuses.
With Epsom Salt, the "therapeutic window," that is the gap between a good thorough purge and a dangerous electrolyte depletion is rather narrow.
Retain the enema 15 minutes, but no longer!! Too much risk of isotonic shock.
If any of the symptoms of electrolyte depletion are present STOP!!
When used as an enema, Epsom Salt is even faster than orally. Bowel movements start in about 15 minutes!!
Epsom Salt is readily available, and inexpensive.
Sooo, Epsom Salt in an enema is a good choice, but ONLY WHEN YOU NEED A THOROUGH PURGE!!
DON'T TAKE IT TOO OFTEN!!!