[FragIt Dan]

I don't think that pH reading is accurate. Unless your top off water is low pH and your aren't letting it stand, or your dKh is way low, that pH is not really possible (pH equilibrium point is almost entirely controlled by ambient CO2). If you are dumping top off water in all at once you might want to check the pH of it first as it may be shocking your tank, or even better yet let it stand for a day before you add it. Your nitrate is a bit of a concern and you list nitrite both at 0 and at 5-10ppm... if it is not zero this is cause for concern. Water changes are a quick way out, but why are they there in the first place?