Hi BB.... I'm on a kindle so it's difficult to see the photo (and I can't see LBF's at all) but white fuzz can often indicate Columnaris or Saprolegnia.
How much Aq salt are you adding? And what's the water temp?
Medications are often metabolized by the liver and excreted by the kidneys. Aq salt is also excreted by the kidneys. So be careful with this. If he shows any signs of bloat or constipation, I would stop/remove the Aq salt.
Bacteria multiply faster in warm water. So if this is a bacterial infection, lowering the temp towards the bottom of the range can help slow down bacterial growth.
That said, if this was bacterial, the Kanaplex should have started to work. Which leads us to another potential cause of white fuzz called Saprolegnia, which is a water mold. Here's a good website that explains the difference and describes how to tell them apart: http://www.americanaquariumproducts.com/columnaris.html
(Will edit this in a minute. The dog needs to go out!)