By the way, I forgot explain this plant is coming to my mother plant, I separated few plantlets I think a year ago. Mother plant is growing in a kind of fagus soil, and this one is growing on Azoo Grower bed, a sort of ADA like soil.
My experience tell me soil are needing few month to start to be usable by the plants... except ADA like soils. I use to store my bleech leaves in a sealed bag with rain water -or RO water-. Few month after storing you can got a paste of fagus leaves debris.
Really I am not sure about what could be doing for removing it... I add the same fungicide as every time, but it seemed not working. I repotted some plant with the most large infestation, after a month of that, white fungus start to be gone.