I had some problems with murk despite washing it all day, but it cleared up soon enough. I haven't had problems with cloudiness after water changes, which is good! I read about the possibility of anaerobic bacteria too, so I bought some Malaysian trumpet snails to help turn it over. I am hoping that between those, and the future pleco and corys there will not be a problem. Also, if you have plants, the roots will help deliver oxygen to the sand. I am not sure how much area away from the plants this affects though, so it probably shouldn't be the only solution.
My pH hasn't changed at all since my cycle completed.