White Fuzz on Phal roots

[myblue66stang]

Hi, a newbie with another question. I recently repotted all of my phals, about a month or two ago. One (phal x intermedia) has developed a white fuzz on two very healthy growing roots. All of the other roots are fine. I have treated it (and all of the other phals to be on the safe side) with Physan, running it through the media. This was about a week ago. However, the fuzz is still there. Is this something to worry about? The roots are a wonderful green and growing fast. Should I retreat in a few weeks? Should I repot? Should I leave it alone? Is there something better to treat it with? It is growing in a bark / cork / spag media, heavy on the chunks, lite on the spag. For me, its a happy medium between all bark and all spag. I water every 3 to 5 days, depending on the weather (overcast vs sunny) and what the roots tell me. Any advice is greatly appreciated. Thanks Cindy