contaminatation

Hey guys I'll keep this brief. I'm starting an African Cichlid tank in a 29 gallon. I attached the heater to the back-side of the tank, with the suction cups on either side of the heater. A week later, I look at the heater's instructions more thoroughly and realize the first instruction says...

i just accidentally dropped a cup of coffee which splattered all over my new betas tank. The feeding whole is small,so I don’t know how much got in there. I tested his ph when I started treating him for possible fin and take rott,though I really believe the culprit was one of his silk but still...