Roots rotting after repotting

[natasa_gr]

Hello to all of you in this board! I am a new member and I am also new to the orchid world! I have watched almost every phalaenopsis related video in youtube, with a preference to MissOrchidGirl's videos! I own 7 phals, the 1st one being a birthday gift from a dear friend in January, the rest all purchased by me.

2 months ago I started repotting my orchids, as 2 of them showed signs of snails. So, I repotted 3 of them in SemiHydro with Leca and 3 in a bark mix medium. Everyone of them has had some roots rotting after the repotting and also the 2 that were in bloom and I put in bark mix so that they are not as shocked and keep the flowers, lost all the blooms anyway...

The last one I don't dare to repot yet, as it has beautiful blooms and I'm afraid she will also drop them...

Is this normal (root rot and loss of blooms after repotting, in any media)? Thanks for your help!