I have a problem with my Amazon Sword; many of the leaves have large brown spots on them. I got these from Petco, and they came in those tubes that the chain stores often carry. Right now I have 2x39w T5 bulbs (6500k) on the tank, and I am dosing Excel and Flourish Comprehensive. My first question is what can I do to keep this from happening? My second question is will the brown leaves ever return to good health, or should I trim them off the plant? Thanks!