i cant imagine it being too dry if there is live plants and you mist twice a day. what do you have for lighting? if the light is too hot it will dry everything up faster. do you have a reading on what the humidity range is?
remember , its ok for the tank to dry out during the day. a constantly moist tank will harbor bacteria, especially with potting soil. try moving to eco earth grinded coco husk. i keep this stuff moist in my red eyed tree frog tank with only a humidifier, i never mist them. i have plants in it as well. and have never seen mold. i have seen mold grow in potting soil 1 day after it gets wet(and it was in a screen tank with plenty of ventilation)
but i am digressing, your problem is shedding. if it is only one gecko that keeps having a shed problem, it might just be that that particular geck has trouble shedding. there is shed- aid products out there, i have never used them so if someone has, could we get some info?
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1.1 Gargoyle geckos
1.1 leucistic leopard gecko
0.0.1 asian golden tree frog
1.0 oriental firebelly toad
0.1 european firebelly toad
1.0 albino betta
1.0 orange tabby
0.0.1 asian painted frog
1.0 broad headed skink
0.0.1 fowlers toad
1.1 red eyed tree frog
1.1 red eared sliders
476.769.47 feeder crickets 