This is how we all learn. You try something and if it does not work you move on.
As long as you are so fearful of the flush, it might take you a couple of times to become successful. Positive thinking is a big help.
To me malic acid is too sour, but I have done 1 tbs apple cider vinegar in 8 oz water instead. Applejuice has too many calories too.
Everybody seems to be doing very well with chanca piedra http://www.ashaninka.com.
Try to make it as simple as possible, no extra herbs etc on the day of the flush.
The basics are epsom, OO, grapefruitjuice (mixed the best with OO, shake hard).