The wick above is a specialty wick material made by "Knowlton Specialty Papers". It needs to be stapled to a thin piece of pine to keep it erect during the treatment period. See the image below for a better view of the wick.
The wick below slips into the PVC Deal™ in the bottom board. The wick also needs to be primed before inserting it into the PVC Deal™ in the bottom board.
There is some brood loss under the wick during the oil and acid treatments. The feeding system using the wicks does not seem to effect the brood under the wick unless the wick is too close to the brood, which prevents the young bees from emerging.
The above comb is from one of our Organic Acid Test hives. The wick touched the comb and the acid soaked into the brood cell cappings and killed the young brood. To eliminate this problem, I made a special PVC Deal™ reservoir with the two wicks running up the sides of the end frames of the brood box where there was honey, not brood. I thought this would eliminate the loss of the brood under the wick, but all this did was prevent evaporation of the acids. Only about 10 ml a day evaporated instead of the 90 - 100 ml required to kill the mites. This is an interesting observation, proving that the bees are very conservative in the placement of heat within the hive. They control the brood nest temperature very well. I then modified the original PVC Deal™ reservoir to place the wicks three frames in from the sides, into the brood area, and then again had excellent results.