Thanks for the clarification nicpett. I defenitely meant over fertilization. I have tested the water pH (I only had some pool water testing strips) and the water I've been using to water the plant has a pH between 6.4 and 6.8. I've tried to mix some of the soil from the pot with the water and test it again, it it indicates a pH of 6.4 or below (the chart isn't very precise).

As for the possibility of the deterioration due to spraying with water and soap, that is possible. However, we only sprayed it 3 days in a row, not a whole week. We did put the plant back under the sun afterward though.

The base leaves are slowly turning yellow. Since the pH is slightly acidic, could it be a deficiency in P, K or B ? Should I add some more fertilizer or something else to raise the pH?

Any idea on what I should do at this point?

Thanks!