How fast does citro-mag make u have a bowl movement

Magnesium Citrate or Citro mag solutions generally produce a bowel movement any where between a half hour to 6 hours.
It also tastes better if it's chilled and poured over ice.
Adding it to ice will not reduce the strength.

i was just wondering, i suffer from IBS, i have my first colonoscopy in 3 weeks, i have to take the citro mag, but i was wondering

 

is it safe enough to say do once a year to keep the "pipes" clean? like could i take a bottle now and then still take 2 in three weeks

or would that be to much? i suffer from so many problems i'll do anything to improve my health! ;-)