possible tmv viras please help

hello all i have problem the last 4 grows in the 4th week of flower ph has droped to about 5 in the run off ec keeps rising even after i ran .5water ph 5.9 for three days and then flushed them to run off .6 ec the next day gave water .5 ec and the runoff was 1.0 leaves start going yellow and fall off from bottom 70% coco 30% perlite one inch clay balls on bottom ive talked to a couple of guys with a few years behind them one said tmv viras the other bacterial draw down theres got to be some one out there thats had this problem i think i have to raise that ph in the medium for those chemicals to be available i run simple a n b flower root conditioner potash and vitamin hormone come on america help an ozzy out