It probably is magnesium deficiency. That is very common. I started taking magnesium supplements (2 500 mg tablets per day) between my last two flushes and noticed that I had a faster reaction to the ES. You definitely want your colon clean prior to flushing so that everything you flush has a clear way out. I used Colosan once a day for four days prior to my last flush and that helped clear things out very well. Hope this helps.