Magnesium sulfate / potassium sulfate / sodium sulfate
"Started Suprep at 2 p.m. Today. Followed advice found on many blogs and was helped. Ate thick lime Jello...used half the amount of water to make it....about one hour before 1st dose of Suprep. Mixed Suprep with room temp Smart Water. Used a quarter lemon  to rub the rim of the container, then held my nose, drank big gulps and basted my tongue with the lemon  after each gulp. Only smelled the grape scent once.  Sipped tea with lemon afterward and drank slowly the next 32 oz of water. Remained standing and walking...no bending or sitting until needed! So far it has been 2.5 hours....no pains, just almost clear. Was necessary to be in the bathroom...not just close! 
Also ate very lightly starting Friday...procedure is tomorrow at 10:30."