Pour only 1/3 of the phospho fleet soda into a FULL glass of cold CLEAR pop, you can add ice, drink it as fast as you can (you'll hardly notice the horrid salty taste of it or the oily consistancy) do this 3 times in total to get one full 45ml bottle of the phospho soda down...my GI gets me to also take 4 dulcolax tabs (all at one time) with tons of water about
4 hours later (after drinking the prep) and this has worked very well to ensure I'm completely cleaned out...
May I also suggest that for the 2-3 days BEFORE you start the prep you stick with mostly a liquid diet, this makes it much easier when the prep runs through you, it'll come faster and much less painful compared to having alot of food inside you being rushed out by the prep...it's also good because it helps keep you hydrated...it's important to follow with plenty of water after you've drank the phospho soda as well.
How quick, varies from person to person once you drink the phospho, but definitely make sure you are close to the toilet from the moment you start drinking it.
Good luck!
:)