I'm trying to dissolve casein in filtered seawater to prepare media (starch casein agar) for the cultivation of marine actinomycetes. I added 2M NaOH dropwise to my chosen volume of seawater until it reached a pH of approximately 8.5 and it's being heated at ~50°C, occasionally stirred. However, it's taken hours for it to dissolve completely. Any suggestions? And is it normal for the solution to look cloudy?