Thinking about it, I remember resolving that the mold could not have started from anything except my tap water. That might sound crazy, but in some areas the pipes either in your home or at the treatment plant can carry mildew spores in massive amounts. When I open my washing machine, dishwasher, smell a dry clean towel or sweatshirt, it smells like mildew bad. It's not subtle, it makes you sick if you're not used to it. So even though the PPM is only 260 out of my tap, I use ONLY R/O water I buy from grocery store water stations or the like. Now it's all I drink, too. Tap water is bad for you and your plants (in most cities).