IMO an "unsuccessful" flush you described implies you have lots of congestion that the 1st flush could not push thru. Think about a natural stone wall--it has rocks with mortar. Your liver probably has stones in the ducts held in with lots of gunk (mortar) in the tissues and between the stones which acts like glue. The key may be increasing the prep which loosens up the gunk, then the stones can be pushed out like bowling balls by the rush of bile from a liver flush.
Consider using Chinese Bitters from sensiblehealth.com which seems to be good at dissolving the gunk. Use it for a week, take a dose 2X per day rather than just 1X. Then in a week add in the malic acid, again heavy dose. Then do another flush. May have to do this heavy prep and flush a few times to achieve a break in the logjam. Heavy prep then flush.
I would take 2 tablespoons of ES 1 hour before flush and increase olive oil and lemon to 2/3 cup. In other words relax the bile ducts and increase the blast effect!
Also IMO take double dose of colosan or Schulze #1 night before flush--insures you will be cleaned out by the next evening. Can eat breakfast, but eat just some fruit for lunch and dinner. This means you have 14 hours for your liver to rest and charge up (from 8AM breakfast to 10 PM). Skip the normal 1st ES dose (you took that colosan night before you will be cleaned out) then double dose of ES before flush.
Heavy prep to loosen gunk. Extra ES at flush to insure bile ducts are relaxed. Extra OO (Olive-Oil) and lemon to increase blast.
Hint: If you can not stand the ES, you can put it in OO (Olive-Oil) empty vitamin capsules, take them with water maybe 30 minutes sooner than if you took ES in water. Also, heat the lemon juice, then mix with olive oil and add some maple syrup. Tastes almost good!