Provap 110 question
Yes, if you have screened bottoms, you need to close the trays.
Entrance reducers should be also on.
The treatment is so fast (about 20 seconds) that you may leave the opening in the entrance reducer open.
When using a 12 V oxalic acid vaporizer, it's better to fully close the entrances (usually with a cloth) to prevent too much oxalic acid gas getting out of the hive. The 12 V vaporizers take up to two and a half minutes to complete the treatment.
The effectivity of the treatment depends on the oxalic acid being distributed throughout the hive, without too much escaping before it turns back into solid-state.
We usually leave the top entrance open (when we see some oxalic leaving through the top entrance, we can confirm that the treatment went through the whole hive.