Ingesting Epsom salt as magnesium replacement didn't work

Flossy. I have been taking the 1030mg magnesium sulfate capsules (Epsom salt) instead of the 420mg magnesium oxide tablets for the past week.

Without warning, I developed severe leg cramps, a sign of magnesium deficiency. My body was not absorbing the magnesium sulfate. The magnesium oxide must have been absorbed because I didn't have leg cramps with it.

The following link says that neither magnesium sulfate or magnesium oxide are well-absorbed. I'm planning to switch to magnesium citrate or another well-absorbed form of magnesium soon since it is such an important mineral.

https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/