Yes, I have 3 large drain holes. I have not flushed them in these buckets although I have been getting plenty of run off so I am pretty sure nothing is built up in there. I used a soil test kit today and the ph was neutral. It is a color coded test so it is not exact but pretty damn close. And as for the moisture levels, I go with the lift the bucket method. The northern light completely drys out within 7 days and the white domina more like 10-12 days. Oh and I also noticed some of the top fan leaves have twisted.