I would try Marcia's Slurry, I have heard about people using it and bringing leos back from deaths door to amazing health.
And leave the mealies in at all times and make sure they are well gutloaded, if the mealies are not gutloaded they are eating the shell with no nutrition and that can cause impaction as well. Dust the mealies too, I use reptivite once a month, herptivite weekly and calcium & mineral 0 daily.
Keep your chin up, you are doing all you can and its hard when they do not do well for us.
This is the slurry recipe located at post:
http://www.faunaclassifieds.com/forums/showpost.php?p=264013&postcount=3
In a blender, combine:
1 small can Hill's A/D pet food (available at most vets)
1/4-1/3 cup Ensure (not chocolate)
1 jar baby food squash
1/4-1/3 cup Pedialite
2 tablets or contents of 2 capsules milk thistle (herbal supplement, liver purifier, found at most drug stores.)
1/2 tsp. each calcium powder and herp vitamin powder
1 large handful of mealworms, added slowly while mixture is blending
Puree all ingredients until completely smooth, and pour into ice cube tray(s) and freeze. Store cubes in zip-lock bag in the freezer until ready to use, then thaw out 1 cube at a time and store in fridge for 2-3 days. I use the empty baby food jar for this purpose, washing it thoroughly after each batch.
Using this mixture, draw a full dropper (eye dropper type) and place a drop on the gecko's nose. It will lick it off, and as it does, slowly squeeze out a little at a time. Most geckos love this food, and will lap it up. Feed them as much as they will take a couple of times a day.
*Lately, I have been adding about 1 tsp. T-Rex Gargoyle MRP to each new thawed out cube.
**Don't tell anyone you put worrms in the household blender!