I have the same problem with my bp viv. No matter what i tried the humidity never went higher than 40 percent, so i purchased a reptifog fogger by zoomed and that has solved the problem i set it for med fog every 3 hrs and it sends the humidity up to 75, it does drop down a bit in the 3 hrs between foggings but not lower than 50. I live on long island and 8 months of the year humidity is not an issue, but in winter between the oil burner and the supplimental wood burning stove the house gets pretty dry.