There is supposed to be pills you can use instead...I can’t take the liquid makes nasty sores in my mouth. For that matter the clear liquid diet the day before and a couple of laxative tabs would probably do the same thing. Drink lots of fluids ... water especially all day. Could do the laxatives for a couple of days in a row just to be on the safe side.
You have to be careful of sodium and potassium loss when cleaning yourself out like that, more so than just with fasting.
Doctors recommend Gatorade or Pedialyte to deal with electrolytes.