I am preparing MS media for plant tissue culture. After getting it autoclaved and letting it cool down, I add silver nitrate in it at concentration of 4mg/L. Sometimes, white ppts are formed as soon as silver nitrate is added which turn brown later on. But sometimes the media looks fine but later on it develops brown precipitates. While I used to prepare it in the same manner for previous batches and never had this issue. I have checked each component of MS media for reaction with silver nitrate. I have noticed formation of white ppts. when silver nitrate is added to only MS salts solution. So, I changed MS salts source. But i am facing same issue again. I need suggestions how to solve this problem.