I'm having a similar problem. I buy in dmem, the cells look good but the media changed colour to pinkish purple within hours. It looked a bit cloudy but I couldnt see anything unusual under the microscope and the cells are growing well (MDCK cells). I removed the media, washed the cellsseveraltimes with PBS, replaced the mediaandagain after afew hours colour changed. Ive never seen this before, co2 fine as is the incubator water level
Any ideas?