While dosing medications may change water parameters, I highly doubt its going to lead to ammonia creation.
Back before I knew what i was doing in this hobby, I dosed melafix in my display tank as well. This is in direct violation of one of the cardinal rules of reef keeping
NEVER dose meds in the display tank.
In any case, its obvious that the only people you're willing to take seriously are those that agree with the conclusions that you have already drawn, so I won't be wasting any more of my time or effort in assisting you with your issues
So by all means, carry on dosing your DT with things that you aren't testing for (because test kits are optional right?) and buying sick fish