My money tree has developed yellow leaves with brown spots throughout the tree. It also has a sticky residue on the underside of the leaves. It has been getting worse over the last few of months. It sits in front of a shuttered window that gets sun about 4 hours a day. I have recently tried watering it whenever the soil feels dry, rather than just once a week. I have also tried rain water gathered from my outdoor pond. It doesn't seem to be helping. Do you have any suggestions?