Well, I use one. Tap water is ph 8, sucks for my plants. Was using distiller, 3 hours per gallon. Went with RO, takes about 12 minutes a gallon,
6.3 ph. That's why I use one. Sheesh, I won't even drink tap water, nor feed it to my pets. Not until RO filtered. If you ever smelled the left over in the Water wise distillers boiler, you wouldn't drink it either.
Bubba