I run 24/7. In the winter with low 20s ambient humidity, the grow room is still around 40s. In the summer the ambient humidity can be as high as 70 in the house with ac. But with the fan on 247 and circulation fans, i havent had any mold or rot issues yet.Hello all. I have a scrubber with a speed regulator and wanted to see what people think it's better, constant on, running on low, or intermittent on/off with somewhat faster speed.