If possible, I would HIGHLY recommend purchasing silica sand, since perlite will likely not help with the drainage problem. Are you pretty much letting the media dry out in that pot? If not, the humic acids will continue to wick up onto the crown. The key is letting the media dry out a lot more if it's still occurring.
Otherwise, it might be beneficial to start off with rinsed media (which is strongly recommended by Tamlin- whom I adapted that rinsing technique from)
As a side note, I actually tried a weird/funny thing that surprisingly worked- I one time had to uproot a plant of D. aliciae that was crowding out another of my sundews. I broke off the roots and tried placing the top of the plant in a shallow clear salad dressing container (not sure what to call it). My initial experiment was to see if the leaves would strike plantlets if the leaves were still attached to the mother plant. I put enough water so the plant was initially submerged, but now the leaves are all growing above the water level. But oddly enough, a year later, the plant has continued growing well, looks healthier than ever, and is developing some really nice-sized leaves and roots. Best part is that humic acids can't develop! I haven't fed it either, so I'm surprised that it's growing this well. So that would be another option for making a back-up... I will try to upload a pic of this in the next few weeks.