Just coming back to the game and wanted to install optifine with a shaderpack, but optifine isn't giving me the clear water option in the quality tab. (I'm pretty sure this is where it used to be located last time I played.)
Have they removed it or have I messed something up during installation or what's going on?
As mentioned in this post in the Optifine thread, the clear water option is redundant in 1.13, so it was removed. Also, re: shaderpacks, most haven't updated to work properly with 1.13 yet, so you might want to hold off on that part. Sildur's is reputed to be about the only one so far that has.