300ppm feed? Seems really low. Get that upto 600-800 from your nutes (excluding tap ppm).
See what happens. Twisting is odd.. could be pH.. try one at a time...
spreadsheet i have in week 7 of ggxww might help you. download from the googledrive link. you can't see the instructions on the google view, but they are there if oyu open in excel, openoffice calc or libreoffice calc etc. (made with libre office calc, free program.