Fuzzy white mold growing on bark mix of repotted Phal

[LizHM]

Hello,
I am new to the orchid board. I have a problem with a Phal that I repotted 1 month ago into "Phalaenopsis Dark Classic Orchid Mix" from repotme containing "Medium Coconut Husk Chips, Medium Sponge Rock, Medium Stalite , Medium Granite Chips, & Chilean 5 Star Premium Sphagnum Moss . " Now the bark is growing a fuzzy white mold. I am not sure if I should repot this plant again. Previously it was growing in sphagnum moss from the store and the roots were rotting. I removed the rotten roots and replanted it in this bark mix, an a ceramic orchid pot with holes for air circulation. It is growing indoors in an east facing room, with a room temp of 72 degrees and is on a humidity tray. I water it once a week. I also recently got a fan for it to increase air circulation. I read about using physan 20 and have ordered it, but did not receive it yet.