I am getting really frustrated with this. I had the tub testing and it was too humid in the 80s, so I put more holes in and more holes in I have two rows each now front and back 5 holes per row so 20 holes and the humidity was 65%. THen I tested another tub with NO holes! and it was 60%??? Using the same two hygrometers to double check (digital). The humidity outside the tubs is in the 50s in my house.