I'm a beginner at this like you, but my understanding is that when you
break
the chloramine bond the chlorine is taken care of but you end up with
nitrates.

You end up with ammonia as far as I can recall, so I'm curious if this could
be affecting my nitrate levels.

I don't know why you'd have 200 ppm of it though. I'm sure
someone else will correct me if that's not right. Also I don't know at
what
level nitrates are harmful to fish. They are good for plants. It is the
ammonia and nitrites that will kill fish.

Another good question. Baensch isn't clear on the effects of high nitrate
levels, nor is there any clear reference on the web. I've heard some people
mention that their fish appear to suffer at 50ppm, but clearly, if my
readings are correct, the tolerable (and thriveable!) level could be MUCH
higher. Thanks for the reply,

Tony