I recently purchased three LBs, at the time of purchase i noticed what looked like hard water stains on the leaves (we live in the Central CA Valley and the water is very hard) other than that they looked pretty healthy..

I cleaned the leaves with a wet paper towel (i think i used filtered water) they looked ok for a couple of days, but now i found very fine white powderlike dust on the leaves, and some of the spots are back. These plants are in soil. I bought them at Lowe's so can I return them if they are sick.

I was planning to tranfer to a waterbase container in the future, I've had a terrible experience with fungus gnats with past houseplants and now only have LB in water.

If i decide to keep these in soil, how much water do they need? I use a water measuring meter...thanks